Статті в журналах: "Alloy layer"

1

Chen, Chang Jun, Qin Cao, Min Zhang, Qing Ming Chang, and Shi Chang Zhang. "Laser Repair Cladding of Ni-Base Alloy on TC2 Ti Alloy." Advanced Materials Research 239-242 (May 2011): 2191–94. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.2191.

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An attempt has been made to fabricate Ni-base alloy layer on the surface of TC2 titanium alloy substrate by laser repair cladding technology for repairing the worn surface of TC2 alloy after in service. Laser cladding is carried out by melting the preplaced Ni-base alloy powder using a continuous wave CO2 laser and using Ar as shielding gas. Microstructure and chemical composition of the cladding coating was revealed by optical microscope (OM), scanning electron microscope (SEM), together with the energy dispersive X-ray spectroscope (EDS). A clad layer with low dilution and metallurgically bonding coating to the substrate could be obtained. A significant improvement in microhardness is achieved in the cladding layer and at the interfacial region. The results showed that laser repair cladding is highly promising technology to restore damaged Ti alloy parts.

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2

He, Qing Kun, Hong Zhi Cui, Shao Hua Huang, Jin Quan Sun, Hong Guang Yang, and Yong Feng Li. "Laser Cladding of Ni-Based Alloy on Mg Alloy with Brass Transition." Materials Science Forum 686 (June 2011): 197–201. http://dx.doi.org/10.4028/www.scientific.net/msf.686.197.

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Laser cladding of Ni-based alloy on Mg-alloy was achieved by using brass as transition layer on substrate. The Ni-based alloy layer free of cracks and porosities was bonded metallurgically with the Mg substrate using brass as the transitional layer. The Ni-based cladding layer was mainly composed of Cr2Ni3, FeNi3, AlNi3 while the content of Mg, Al, Cu and Zn is very low in the cladding layer. Microhardness and the wear resistance of the sample were tested, whose results indicated that microhardness and wear resistance increased 12.8 times and 13.3 times, respectively compared with the substrate. In addition, the corrosion potential (Ecorr) of the sample was much higher than that of untreated materials.

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3

Zeng, Yan, Xiao Yang Huang, Wei Dong Zhou, and Sheng Kai Yu. "A Numerical Study on Heat Transfer and Lubricant Depletion on an Anisotropic Multilayer Hard Disk." Applied Mechanics and Materials 232 (November 2012): 770–74. http://dx.doi.org/10.4028/www.scientific.net/amm.232.770.

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This paper presents a numerical investigation on the effect of thermal anisotropy of the top layer alloy on heat transfer and lubricant depletion on the disk surface in a heat-assisted magnetic recording (HAMR) system. The disk consists of multilayer structures and a thin layer of lubricant on the top surface. Cases under different laser powers and initial lubricant film thicknesses are examined. The top-layer alloy thermal anisotropy does show non-negligible effect on the heat transfer and lubricant depletion. With the top-layer alloy being more anisotropic, higher temperature increase and lager lubricant depletion can be observed on the disk surface. The results also show that the thermal anisotropy effect is more significant under a lower laser power but nearly keeps no much difference under different initial lubricant film thicknesses. Thus it is of importance to include the thermal anisotropy effect of the top-layer Co-alloy when simulating the heat transfer and lubricant depletion in practical multilayer HMAR systems, especially for the cases under the condition of lower laser power, as the effect cannot be neglected under such conditions.

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4

Svéda, Mária, and András Roósz. "Development of Amorphous and Microstructured Surface Layer by Laser Surface Treatment." Materials Science Forum 752 (March 2013): 175–82. http://dx.doi.org/10.4028/www.scientific.net/msf.752.175.

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The aim of the research was to develop an amorphous and microstructured layer on non-amorphous alloys by laser surface treatment. The as-prepared Cu based master alloy ingots were imbedded in a metallic sinking with Wood metal to assure the good thermal conductivity during the laser treatment. The laser remelting, alloying and coating techniques were applied from the laser surface treatment techniques. The surface layer production and a subsequent rapid cooling were performed using CO2 laser and pulse and continuous modes of Nd:YAG laser. The characterization of the microstructure of the resulting surface layer was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Actual remelting on substrates showed that the process of laser remelting is a suitable technique for production of metallic glasses as surface layers. The amorphous layer up to 250 m in depth can be produced by laser surface remelting on Cu46Zr42Al7Y5 alloy.

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5

Zhang, Yuan Bin, Huai Xue Li, and Kai Zhang. "Investigation of the Laser Melting Deposited TiAl Intermetallic Alloy on Titanium Alloy." Advanced Materials Research 146-147 (October 2010): 1638–41. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1638.

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To improve the wear resistance of Titanium alloy, TiAl intermetallic claddings were fabricated on TC4 substrate using laser melting deposition technology. Optical microscope, scan electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction meter were applied to investigate the deposited TiAl layer and their interface with substrate. Using hardness tester and M-2000 wear testing machine, hardness, frictional coefficient and wear resistance of the TiAl layers and TC4 alloy were tested. It was indicated that the deposited TiAl layers were well integrated with TC4 substrate, γ-TiAl and Ti3Al dual phase microstructure was formed in the deposited layer. With higher hardness and lower friction coefficient, the deposited TiAl layer improved the wear resistance obviously comparing to TC4 titanium alloy substrate.

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6

Ohno, H., Y. Araki, and K. Endo. "ESCA Study on Dental Alloy Surfaces Modified by Ga-Sn Alloy." Journal of Dental Research 71, no. 6 (June 1992): 1332–39. http://dx.doi.org/10.1177/00220345920710061101.

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A new, simple surface modification method for adherend metals has been developed. It gives high bond strength and superior water durability to dental precious-metal alloys bonded with 4-META/ MMA-TBB resin. However, there was no effect on the bonding of Ag-In-Zn alloy and base-metal alloys. In the present study, the alloy surfaces modified by the new method were analyzed by ESCA and SEM for determination of details of the modification effect. A new alloying layer containing Ga and Sn was formed on the precious-metal alloys. The main factor for excellent adhesion to be achieved was the formation of a very thin layer of Ga 2O3 and SnO2, less than 1-2 nm thick, on the alloy surface. A thicker modified layer, as formed on the Ag-In-Zn and Ni-Cr alloys, led to low bonding ability.

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7

Yan Ruifeng, 颜瑞峰, 郭亮 Guo Liang, 张庆茂 Zhang Qingmao, 周永恒 Zhou Yongheng, and 张健 Zhang Jian. "Laser Cladding Co-Based Alloy Layer on AZ91D Magnesium Alloy and Properties." APPLIED LASER 32, no. 3 (2012): 175–79. http://dx.doi.org/10.3788/al20123203.175.

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8

Grigoryev, Alexey, Igor Polozov, Anatoliy Popovich, and Vadim Sufiyarov. "Application of additive technologies for synthesis of titanium alloys of Ti-Al, Ti-Al-Nb systems of elemental powders." SHS Web of Conferences 44 (2018): 00037. http://dx.doi.org/10.1051/shsconf/20184400037.

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Additive technologies are one of the drivers for development of new industrial revolution. For developing additive production it is necessary to expand the nomenclature of materials used in the form of powders. One of the ways for synthesizing new alloys in additive technologies is applying a mixture of powders as primary components; the powders correspond in their composition to the given alloy. The technology of selective laser melting enables synthesizing the necessary alloy by means of layer by layer melting of a powder mixture. A study of the process of Ti-5Al and Ti-6Al-7Nb titanium alloys synthesis of elemental powders by means of selective laser melting was undertaken in this work. Microstructure, chemical composition, mechanical properties of the synthesized alloys were studied and also the influence of thermal processing on the microstructure of the Ti-6Al-7Nb alloy obtained of elemental powders was explored.

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9

Svéda, Mária, Dóra Janovszky, K. Tomolya, J. Sólyom, G. Buza, and A. Roósz. "Nanostructure Layer Formation on Cu-Zr-Al Alloy during Laser Remelting." Materials Science Forum 729 (November 2012): 272–77. http://dx.doi.org/10.4028/www.scientific.net/msf.729.272.

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This paper reports laser remelting of crystalline Cu based alloys in order to produce amorphous layer on the surface. The as prepared Cu based master alloy ingots were imbedded in a metallic sinking with Wood metal to assure the good thermal conductivity during the laser treatment. The laser remelting of a thin surface layer and a subsequent rapid cooling of it was performed using impulse and continuous mode of Nd:YAG laser. In respectively the impulse mode the laser power and the interaction time were 1.5; 2 kW and 20÷100 ms. In the continuous mode the laser power was 2 kW, and the laser scan speed was 80÷120 mm/s. The characterization of the microstructure of surface layer was performed by XRD, scanning electron microscopy and microhardness measurements.

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10

Cai, Xun, Xiaoyu Yang, Tao Zhao, Liuhe Li, and Qiu Long Chen. "Laser Surface Cladding of Al-Si Alloy." Key Engineering Materials 297-300 (November 2005): 2813–18. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2813.

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The mixture of Ni based alloy powder and WC particles were used as a feeding material to modify the surface properties of cast Al-Si alloy using a CO2 continuous transverse flow laser beam with maximum power of 10 kW. Microstructures and chemical components of the laser surface cladding (LSC) layers were studied using SEM, XRD, TEM and EDS. It is shown that the LSC layers were composed of γ-（ Ni, Cr, Fe, W）matrix phase and many enhancing phases, such as Ni2Al3, Ni3Al, WC, W2C, Cr2B, etc.. The microstructure of the LSC layers was greatly affected by the scanning rate b V and the powder of feeding rate p m under the same laser power. With the increasing of b V and p m , the dissolution phenomenon of WC particles was improved; the length, the diameter and the amount of the acicular constituent were markedly reduced. Microhardness and wear resistance tests were also performed: the average microhardness of the LSC layers was around 5.1 to 5.9GPa, which was five times higher than that of the Al-Si substrate. The wear resistance of the layer was about 20 times as big as that of cast Al-Si alloy when P=6kW, b V =13.3mm s-1, p m =100mg s-1, L=500N. The results showed that the mechanical properties of LSC layers on cast Al-Si alloy can be markedly enhanced with proper processing parameters. However, due to the sudden change of physical and mechanical properties between laser modified layer and substrate, some defects, especially crack, actually occur in the surface modified layer and the interface zone. And finally Ni/WC surface gradient layer was obtained on cast Al-Si alloy through thrice laser scanning technique. The microhardness of the laser gradient layer gradually changed from surface to substrate, so that it can reduce stress concentration in the whole laser surface layer, especially in the interface zone.

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11

Voropaev, Alexander, Maxim Stramko, Alexander Sorokin, Ivan Logachev, Mikhail Kuznetsov, and Sergey Gook. "Laser welding of Inconel 718 nickel-based alloy layer-by-layer products." Materials Today: Proceedings 30 (2020): 473–77. http://dx.doi.org/10.1016/j.matpr.2019.12.399.

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12

Zhang, Chun Hua, Yu Xi Hao, Lin Qi, Fang Hu, Song Zhang, and Mao Cai Wang. "Preparation of Ni-Base Alloy Coatings on Monel Alloy by Laser Cladding." Advanced Materials Research 472-475 (February 2012): 313–16. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.313.

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Abstract. The paper presents the results of a study concerned with the surface hardening of Inconel 625 alloys and Ni-base alloy powder on Monel alloy by electro spark deposition and laser cladding processes. The microstructure, the phase composition and the microhardness of samples are investigated by SEM, EDS, XRD and microhardness instrument. It is shown that, the matrix phase is mainly made up of dendritic structure (γ-Ni), interdendritic eutectic phase (Ni3(B,Fe,Si)) and some precipitates (Cr7C3, Cr23C6). Additional, the microhardness of laser cladding layer can be substantially increased, duo to formation of precipitates.

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13

Zhang, Chao, Jianjun Song, and Jie Zhang. "Optimization of Laser Recrystallization Process for GeSn Films on Si Substrates Based on Finite Difference Time Domain and Finite Element Method." Journal of Nanoelectronics and Optoelectronics 15, no. 3 (March 1, 2020): 376–83. http://dx.doi.org/10.1166/jno.2020.2705.

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GeSn alloy on Si substrate has the advantages of high carrier mobility, high radiation recombination efficiency, compatibility with the Si process, and is widely used in the field of semiconductor optoelectronics. However, due to the high lattice mismatch between the GeSn epitaxial layer and the Si substrate, how to prepare a perfect GeSn film on the Si substrate is an issue. The 808 nm continuous wave laser recrystallization technology can significantly improve the quality of the GeSn alloy epitaxial layer by melting and recrystallization, which provide another technical way for solving this problem. Optimized laser recrystallization related process parameters is necessary when laser recrystallization technology is used to prepare high quality GeSn alloy on Si substrate. For this purpose, the absorption, reflection and transmission models of GeSn alloy epitaxial layer/Si substrate system irradiated by 808 nm continuous wave laser are established using finite difference time domain software FDTD Solutions. The thickness-related process parameters of GeSn alloy epitaxial layer and SiO2 capping layer are optimized. In addition, the temperature distribution model of 808 nm continuous wave laser irradiation of GeSn alloy epitaxial layer on Si substrate system is obtained by COMSOL Multiphysics simulation. The process parameters related to laser recrystallization temperature are optimized and listed, which can be used as important technical references for the growth of low defect density GeSn layer on Si substrate assisted by the laser recrystallization technology.

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14

Ogura, Tomo, Syunsuke Netsu, Tetsuya Yokochi, and Kazuyoshi Saida. "Dissimilar Metal Joining of A5052 Aluminum Alloy and AZ31 Magnesium Alloy Using Laser Brazing." Materials Science Forum 879 (November 2016): 2532–36. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2532.

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The microstructure and mechanical properties of a joint produced by laser brazing between A5052 and AZ31 with AZ61, AZ91 and AZ125 filler metal was investigated. The effects of filler metals on joint characteristics are also discussed. Measurement of microstructural factors in the laser brazed joint revealed that increasing the laser power results in a decrease in the weld toe angle and an increase in the bead width, which indicates superior wettability. A high strength laser brazed joint can be achieved through the combination of good wettability and a thin intermetallic layer produced by a laser power of 590 W in a brazed joint with AZ125 filler metal Any further increase in power, however, results in a rapid increase in the thickness of the intermetallic compound (IMC) reaction layer. The superiority of the brazed joint with AZ125 filler metal is due to its lower melting point than that of AZ61 and AZ91 filler metal.

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15

DUDEK, KAZIMIERA, WOJCIECH SZCZYPINSKI-SALA, and JANUSZ LUBAS. "INFLUENCE OF LASER BORIDING ON THE FRICTION AND WEAR OF SLIDING COUPLES WITH BEARING ALLOYS." Surface Review and Letters 27, no. 01 (March 26, 2019): 1950084. http://dx.doi.org/10.1142/s0218625x19500847.

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The present study discusses the influence of laser borided surface layer on the parameters of sliding couples lubricated by engine oil. The borided layer was created by laser remelting of a surface layer of steel samples coated with amorphous boron. The study of friction, wear, and lubrication was conducted on the pairs made of steel AISI 5045 and SAE-783 and SAE-48 bearing alloys which were lubricated with 15W/40 engine oil. The research showed important differences in the friction coefficient and temperature in the tested couple with laser borided surface layer. In the couples containing the counterparts with SAE-783 bearing alloy, the tested parameter of friction was higher than in the couple composed of counterparts with SAE-48 bearing alloy. The counterparts with SAE-48 showed more intensive wear in contact with the laser borided surface layer than the counterpart with SAE 783. The process of friction at the contact area of the sliding couple with laser borided surface layer leads to the destruction of the lubricating properties of 15W/40 engine oil and reduces its resistance to scuffing and seizure.

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16

Zhao, X. R., Dun Wen Zuo, H. Cheng, Q. T. Li, S. Dai, and S. S. Feng. "Microstructure and Properties of Laser Cladding Co-Based Alloy Layer." Advanced Materials Research 764 (September 2013): 47–53. http://dx.doi.org/10.4028/www.scientific.net/amr.764.47.

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The Co-base alloy laser cladding layer was coated on the 2738 mold steel surface by using the TJ-HL-5000 transverse-flow CO2 continuous laser. The morphology and hardness were investigated by metallography microscope, scanning electron microscopy (SEM), X-ray diffraction (XRD) and microhardness tester. The metallography microscope and SEM investigations show that from interface to surface along the cross section direction, the cladding layers consist of plane crystal layer, columnar crystal layer, dendrites layer and surface cellular crystal layer, respectively. XRD results indicate that the cladding layer is made of γ-Co, Cr23C6, MoC, FeCr and Co3Mo2Si phases. The micro-hardness of the laser cladding coating was about 900-1100HV1, 3 times or more of the steel substrate. And the mechanisms of microstructure formation and strengthening are investigated.

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17

Sato, Hisashi, Yuichi Kubota, Eri Miura-Fujiwara, and Yoshimi Watanabe. "Effects of Phase Transformation Temperature on Formation of Wear-Induced Layer in Fe-Ni Alloys." Materials Science Forum 654-656 (June 2010): 1227–30. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1227.

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Effects of the transformation temperature on formation behavior of the wear-induced layer in Fe alloys are investigated using Fe-33mass%Ni and Fe-30mass%Ni alloys. Martensitic transformation temperature (Ms) and reverse transformation temperature (As) of Fe-33mass%Ni alloy are lower than those of Fe-30mass%Ni alloy. Microstructure of the wear-induced layer in Fe-33mass%Ni alloy was single austenite phase (γ) with fine grain. On the other hand, the wear-induced layer in Fe-30mass%Ni alloy consists of martensite (α’) and γ with fine structure. This difference is due to the difference of As between these Fe-Ni alloys. Moreover, the microstructure of the wear-induced layer has no dependence on the distribution of α’ in initial microstructure. From obtained results, it is concluded that the formation of the wear-induced layer in Fe alloys is mainly affected by As.

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18

Ye, Xiaoyang, Mingxing Ma, Wenjin Liu, Lin Li, Minlin Zhong, Yuanxun Liu, and Qiwen Wu. "Synthesis and Characterization of High-Entropy Alloy FeCoNiCuCr by Laser Cladding." Advances in Materials Science and Engineering 2011 (2011): 1–7. http://dx.doi.org/10.1155/2011/485942.

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High-entropy alloys have been recently found to have novel microstructures and unique properties. In this study, a novel FeCoNiCuCr high-entropy alloy was prepared by laser cladding. The microstructure, chemical composition, and constituent phases of the synthesized alloy were characterized by SEM, EDS, XRD, and TEM, respectively. High-temperature hardness was also evaluated. Experimental results demonstrate that the FeCoNiCuCr clad layer is composed of only BCC and FCC phases. The clad layers exhibit higher hardness at higher Al atomic content. The AlFeCoNiCuCr clad layer exhibits increased hardness at temperature between 400–700°C.

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19

Fan, Fei, Hao Sun, Di Zhao, and Jiang Bo Sha. "Effect of Mo on the High Temperature Oxidation Behavior of Co-Al-W Based Alloys." Materials Science Forum 747-748 (February 2013): 754–59. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.754.

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2 at.% and 4 at.% Mo were added to Co-9Al-9W-2Ta-0.02B alloy to replace W (hereafter referred to as the alloys of 2Mo and 4Mo, respectively; Mo-free alloy was referred to as the 0Mo alloy). The effects of Mo additions on the high temperature oxidation behavior of the alloys at 800 °C in air have been studied. The results indicated that, after oxidation in air at 800 °C for 100 h, the oxide film of the 0Mo alloy remained intact, but the cracking and spallation of the oxide film took place in the alloys of 2Mo and 4Mo. Oxidation kinetic curves revealed weight gain per unit area of the 0Mo alloy was 36.86 mg·cm-2, which was lower than that of the alloys of 2Mo (65.16 mg·cm-2) and 4Mo (48.54mg·cm-2). These suggested that the 0Mo alloy displayed superior oxidation resistance compared to the alloys of 2Mo and 4Mo caused by the formation of volatile MoO3 oxide, and sharp compressive stress formed in the outer layer during the oxidation. The oxide layer was composed of three layers of the Co3O4 + CoO outer layer, middle complex oxide layer containing Co, Al and W (Mo), inner Al2O3 layer and γ/Co3W zone adhere to the γ/γ' substrate.

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20

Fei, Jixiong, Guoliang Liu, Kaushalendra Patel, and Tuğrul Özel. "Effects of Machining Parameters on Finishing Additively Manufactured Nickel-Based Alloy Inconel 625." Journal of Manufacturing and Materials Processing 4, no. 2 (April 21, 2020): 32. http://dx.doi.org/10.3390/jmmp4020032.

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Metal additive manufacturing processes such as selective laser melting (SLM), laser powder bed fusion (L-PBF), electron beam melting (EBM) and laser metal deposition (LMD) can produce additively manufactured nearly fully dense parts with high geometrical complexity. These are often used as components in automotive, aerospace and medical device industries. Finish machining of these components is required to achieve the desired surface finish and dimensional tolerances. The investigations on additively manufactured alloys, as reported in the literature, indicate that a layer-wise scan strategy (orthogonal or layer-to-layer rotation) and process parameters have significant influences on the resultant microstructure which affects the final mechanical properties and fatigue life. The solidification microstructure depicts that growth directions of columnar grains and sizes of cellular grains that are affected by the layer-wise scan strategy. This paper presents experimental investigations on finish milling parameters on a nickel-based alloy manufactured with L-PBF using two distinct layer-wise scan strategies. The results reveal some effects of milling direction against the layer-wise build direction. The effects of cutting speed and feed rate on resultant cutting forces, chip formation, as well as surface finish at various cutting orientations in nickel-based alloy workpieces are reported.

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21

Pakieła, Wojciech, Tomasz Tański, Krzysztof Labisz, Katarzyna Pakieła, and Zbigniew Brytan. "Structure and Mechanical Properties of Composite Layers Prepared by Laser Alloying of Aluminium Alloy." Solid State Phenomena 275 (June 2018): 53–65. http://dx.doi.org/10.4028/www.scientific.net/ssp.275.53.

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Increasingly high expectations for modern engineering, make the constantly being sought-after new processes giving traditional materials new, better features. Nowadays, next to the classic heat treatments, advanced technologies are being used increasingly, leading to much better results than ever before. The most commonly used technologies that allow for obtaining new, enhanced properties of various metal alloys in the area of surface engineering include, among others laser surface treatment. The main objective of this paper was to analyze the influence of laser surface treatment on structural change and mechanical properties improvement of Al-Mg alloy by VC alloying. The remelted layer on the aluminium alloy surface was obtained using high power fiber laser "Ytterbium Laser System YLS-4000". The surface sample was remelted using a rectangular laser beam (2 x 4mm) with a power of 3 kW (1.53e+4w/cm2). Scanning speed of the laser beam was 0.8 cm/s (0.48 m/min). The remelting area has been protected by the use of technical argon blowing. During the process, sintered particles of vanadium carbide with an average size of about 50-100 μm was introduced into the liquid metal. Ceramic powder in the remelting volume was fed with a pressure feeder (constant rate of 5 g/min). As a substrate, the ENAC AlMg3 alloy has been used. During the laser treatment, a composite layer with much better mechanical properties was obtained comparing the base material. The average hardness of the layer was about 19 HV0.1higher than that of the base material. Chemical analysis, carried out with the EDS (energy dispersive spectroscopy) detector and transmission microscope revealed many undissolved powder particles used in the alloying process as well as those of Al8V5precipitated in the Al-Mg matrix.

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22

Bhola, Rahul, and Brajendra Mishra. "Characterization of a Biomedical Titanium Alloy Using Various Surface Modifications to Enhance its Corrosion Resistance and Biocompatibility." Materials Science Forum 706-709 (January 2012): 105–12. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.105.

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Ti6Al4V titanium alloy has been characterized for its prospective applications as an implant material. The surface treatments performed have brought about enhanced surface properties of these alloys and have produced corrosion resistant oxide films with increased bioactive properties. Characterization of the alloy surface has revealed the presence of a duplex oxide structure over the surface treated specimens, composed of an inner barrier layer and an outer porous layer. The inner barrier layer has imparted a high corrosion resistance to the alloy while the outer porous layer which is responsible for the increased roughness of the surface treated alloy specimens, has encouraged formation and deposition of apatite into the oxide pores and further resulted in an increase in cell adhesion over the alloy surface. Anodization and heat treatment procedures have proved advantageous to titanium alloys in terms of producing oxide films that can offer these alloys an improved biological performance.

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23

Fu, Guang Yan, Xin Zhao, Qun Liu, and Yong Su. "Hot Corrosion of Cobalt-Based Alloy with (Na, K)₂SO₄ Coating at 900 °C." Advanced Materials Research 194-196 (February 2011): 1305–8. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.1305.

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The hot corrosion behavior of pure Co, Co-10Cr and Co-10Cr-5Al alloys coated with (4～4.5) mg/cm2 (Na, K)2SO4 deposits has been studied at 900 °C in air by thermogravimetry and SEM/EDX analysis. The results show that hot corrosion rate of Co-10Cr alloy was obviously higher than that of Co-10Cr-5Al alloy and hot corrosion rate of pure Co was between those of the two cobalt-based alloys. Both alloys produced complex corrosion scales, containing an outermost layer of pure cobalt oxide and an inner layer where the oxides of both alloy components were simultaneously present on the Co-10Cr alloy, while a middle layer containing CoO and Cr2O3 and an inner layer of Al2O3 with a few aluminum sulfides appeared on the Co-10Cr-5Al alloy. The results were interpreted by taking into account the effect of active element and hot corrosion mechanism.

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24

Enomoto, Masatoshi, Sadao Kokubo, and Kazuhiro Nakata. "Surface Treatment of Aluminum Alloy with Laser Irradition to Increase Wear Resistance." Materials Science Forum 539-543 (March 2007): 404–10. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.404.

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Laser irradiating process with Nd-YAG laser is investigated in order to improve the adhesion and wear resistance of low pressure plasma sprayed layer on the surface of aluminum extruded shape using the atomized powder of Al-50mass%Fe, Al-15mass%Fe-17mass%Si and Al-50mass%Si. The effect of pulse energy of laser beam on the microstructure, micro hardness and wearing rate of these laser irradiated layers are evaluated. Laser irradiated layers have appeared more smooth surface and better adhesion than as sprayed layer. Depth profile of micro hardness where laser irradiated is respectively kept constant. In the microstructure of laser irradiated layer of Al-50mass %Fe, fine needle-like Al3Fe and massive Al2Fe are dispersed. Micro hardness increases with decrease of the pulse energy of laser beam However, the wearing rate of laser irradiated layer increases due to the initiation of cracking. In the microstructure of laser irradiated layer of Al-15mass%Fe-17mass%Si, ultra fine needle-like and massive (Al, Fe, Si) ternary crystals are aggregated. In the microstructure of laser irradiated layer of Al-50mass%Si, ultra fine hyper-eutectic structure is observed. Micro hardness of these layers are HV250-350, HV150-200, respectively and wearing rate of these layer are 1/7 or less than anodized surface.

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25

Zhang, Chun Hua, Li Wen Tang, Fang Hu, Song Zhang, and Hau Chung Man. "Study on Wear and Corrosion Properties of Ti6Al4V Alloy by Laser Gas Nitriding." Advanced Materials Research 299-300 (July 2011): 188–92. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.188.

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Titanium alloys have successfully been used as surgical implants. Laser gas nitriding (LGN) is an effective method to improve the wear and corrosion resistance of titanium alloys. A nitride strengthened uniform layer, free of cracks, was obtained on the Ti6Al4V alloy by irradiating with a continuous wave Nd-YAG laser in a N2environment. The microstructure, electrochemical corrosion and tribological behavior of the alloy before and after LGN were studied by SEM, XRD, potentiostat, microhardness tester and tribometer. The results show that the performance and composition of the surface of the Ti6Al4V alloy were significantly improved by LGN, with better corrosion resistance in simulated body fluid and better wear resistance.

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26

Lv, Hao, Zhijie Li, Xudong Li, Kun Yang, Fei Li, and Hualong Xie. "Effect of Vanadium Content on the Microstructure and Mechanical Properties of IN718 Alloy by Laser Cladding." Materials 14, no. 9 (May 1, 2021): 2362. http://dx.doi.org/10.3390/ma14092362.

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Microalloying vanadium can change the segregation state of Nb element in IN718 alloy, reduce the formation of harmful Laves phase and refine the dendritic structure of IN718 alloy during the laser process. Therefore, IN718 alloys with V content from 0.081 to 1.88 wt.% were prepared and evaluated. Metallographic microscopy and scanning electron microscopy were used to observe the corresponding morphology, structure, and distribution of elements. First of all, it was found that the addition of V refines the grain size of IN718 alloy and reduces the primary dendrite arm spacing. Secondly, adding V to IN718 alloy can reduce the porosity of the cladding layer. The elements are uniformly distributed in the cladding layer, and the addition of vanadium reduces the segregation degree of the Nb element, which is conducive to homogenization. In addition, microhardness and residual stress were also investigated. Finally, the addition of vanadium was shown to have no apparent effect on the tensile strength and yield strength but can significantly improve the elongation of IN718 alloy. In conclusion, the microstructure and mechanical properties of IN718 alloy with 0.081 wt.% vanadium content provide a new solution to improve the application level of IN718 alloy in laser cladding.

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27

Zhu, Shichao, Wenliang Chen, Xiaohong Zhan, Liping Ding, and Junjie Zhou. "Parameter optimisation of laser cladding repair for an Invar alloy mould." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 8 (October 11, 2018): 1859–71. http://dx.doi.org/10.1177/0954405418805653.

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Laser cladding repair is an advanced technology for repairing Invar alloy moulds; however, the influences of various processing parameters on the quality of the Invar alloy moulds have yet to be determined. To explore the optimisation of laser cladding repair parameters, analyses of the geometric features and microstructure of the cladding layer were conducted. First, the influences of different powder feeding rates and scanning speeds on the dilution rate of the substrate were investigated by establishing a mathematical model of the laser power attenuation. Next, the influences of the parameters on the geometric features of the cladding layer were analysed. Finally, the influences of the parameters on the microstructure of the cladding layer were evaluated. At a laser power of 2300 W, a scanning speed of 3 m/min, and a powder feeding rate of 9 g/min, the best results of the width, height, dilution rate, roughness, and contact angle of the cladding layer were obtained. The results of this study indicated that excellent metallurgical bonding occurred between the cladding layer and the interface layer, and that the intended geometric features and desired microstructure of the cladding layer were obtained.

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28

Hirose, Akio, Fumiaki Matsui, Hirotaka Imaeda, and Kojiro F. Kobayashi. "Interfacial Reaction and Strength of Dissimilar Joints of Aluminum Alloys to Steels for Automobile." Materials Science Forum 475-479 (January 2005): 349–52. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.349.

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In the present study, we fundamentaly analyzed the interfacial reaction and evaluated the joint strength in dissimilar diffusion bonding of Al alloys to steels. The growth of the reaction layer consisting of FeAl3 and Fe2Al5 intermetallic compounds followed the parabolic growth low. The joints with 5000 series Al alloys had a higher growth rate of the reaction layer than the joints with A6061 Al alloy. The joints of A6061 Al alloy to HT980steel had the lowest growth rate of the reaction layer. The joint strength depended on the thickness of the reaction layer. The A6061 Al alloy/steel joints had the maximum joint strength at around 1µm of average reaction layer thickness.

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29

You, Ming Lin. "The Effect of Laser Processed Nano-SiC-Ni Metal Ceramic on the Surface Properties of the Iron-Based Material." Applied Mechanics and Materials 52-54 (March 2011): 953–58. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.953.

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In this article, we have carried out the Ni based self fluxing alloy powder and studied the effect on the laser alloying of 45steel layer which contains different weight percentage of nano-SiC powders. Experimental results show that the alloy layer which obtained by the optimized laser alloying process parameters (I = 38A, V = 100 mm / min, Δf=10mm, Ar gas protection) is smoothness, fineness, hardness and have a good metallurgical bonding. The test of tribological wear experiments shows that the wear capability of Ni-based powder made of laser alloyed layer is more excellent than that of the hardened 40Cr steel. And the tribological wear capability of the Ni-based alloy with SiC made of laser alloyed layer has been further improved. In the same process conditions, the addition of 20% nano-SiC is the best.Salt spray test shows that both the Ni and Ni/SiC composite coatings' corrosion is much stronger than that of the 45steel substrate. But with the added amount of nano-SiC increased the resistance of alloying layer corrosion decreased slightly. Finally, this paper use Grey comprehensive evaluation model to value the quality of the alloy layer. The evaluation vector shows that the laser alloyed layer which added 20% SiC has optimal overall performance.

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30

Swain, Aurabinda, Piru Mohan Khan, Prasenjit Rath, and Anirban Bhattacharya. "Modeling layer-by-layer laser melting and solidification of binary alloy powder bed." Journal of Laser Applications 33, no. 4 (November 2021): 042040. http://dx.doi.org/10.2351/7.0000541.

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31

Kieruj, Piotr, Natalia Makuch, and Mateusz Kukliński. "Characterization of laser-borided Nimonic 80A-alloy." MATEC Web of Conferences 188 (2018): 02003. http://dx.doi.org/10.1051/matecconf/201818802003.

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Nimonic 80A-alloy belongs to Nickel-based superalloys. Many of them are used in variety branches of industry due to high strength and resistance in aggressive conditions. Moreover, its mechanical properties are kept in high temperature. However, these materials should be coated by appropriate wear protection, under conditions of considerable mechanical wear. Unfortunately, the production of thick borided layer in diffusion boriding required high temperature and long duration of this processes. Therefore, in this study instead conventional diffusion process laser boriding was applied in order to produce boride layer on Nimonic 80A-alloy substrate. Laser alloying is the high-tech process which allows to modify the chemical composition of the surface. Laser boriding was arranged as a single tracks, therefore it was possible to evaluate the influence of laser treatment parameters on thickness and hardness of produced layers. The laser beam power P, laser scanning speed vl and laser beam diameter dl were the variable parameters used during laser alloying.

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32

Xie, Changsheng. "Evaluation of alloy element redistribution within laser-melted layer." Surface and Coatings Technology 113, no. 1-2 (March 1999): 1–4. http://dx.doi.org/10.1016/s0257-8972(98)00716-6.

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33

Yang, Chengjuan, Xuesong Mei, Wenjun Wang, Kedian Wang, and Gedong Jiang. "Recast layer removal using ultrafast laser in titanium alloy." International Journal of Advanced Manufacturing Technology 68, no. 9-12 (March 1, 2013): 2321–27. http://dx.doi.org/10.1007/s00170-013-4849-5.

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34

Szafarska, M., J. Iwaszko, K. Kudła, and I. Łegowik. "Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment." Archives of Metallurgy and Materials 58, no. 2 (June 1, 2013): 619–24. http://dx.doi.org/10.2478/amm-2013-0047.

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The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

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35

Saprykina, Natal'ya, Aleksandr Saprykin, Egor Ibragimov, and Margarita Himich. "MODE INFLUENCE OF SELECTIVE LASER IMPACT UPON POROSITY OF SAMPLES OF COBALT, CHROMIUM AND MOLYBDENUM POWDERS." Bulletin of Bryansk state technical university 2021, no. 8 (August 9, 2021): 22–28. http://dx.doi.org/10.30987/1999-8775-2021-8-22-28.

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The purpose of this investigation consists in the analysis of possibility to obtain products by means of the SLP method using powders of cobalt, chromium and molybdenum having considerable difference in melting temperatures of cobalt (1768ºC), chromium (2130ºC) and molybdenum (2890ºC), density, thermal conduction and solving for the optimum technological modes of powder composition melting to obtain samples with lower porosity. The investigation methods include methods of physical material science. Investigation results and novelty: a procedure for obtaining a powder composite of the cobalt-chromium-molybdenum system for selective laser melting is developed. There are carried out experimental investigations on the selection of optimum technological modes for the layer-by-layer laser melting of a cobalt-chromium-molybdenum alloy of powder composition. A method for layer-by-layer laser synthesis for the solution of a principle matter – possibility for the synthesis of the products of cobalt chromium and molybdenum powders having a considerable difference in melting temperatures, density, heat conductivity and so on. The investigations of model alloy samples of cobalt-chromuim-molybdenum system obtained through the method of layer-by-layer laser synthesis on optimized technological modes through the methods of scanning electronic microscopy allow defining sample porosity. The generalization of obtained numerical and experimental investigation results and definition of essential conditions for selective laser melting allow optimizing modes and parameters of the synthesis. Conclusions: the optimum modes of selective laser melting for obtaining the samples with the powder composition of 66 mas. % Co, 28 mas. % Cr, 6 mas.% Mo through the method of selective laser melting with minimum porosity are: laser capacity P=100Wt, scanning rate v=350mm/s, modulation 5000Hz, scanning pitch s=0.1mm, layer thickness h=0.03mm, melting process takes place in protective argon environment.

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36

Xu, Zhidong, Dengzhi Wang, Wenji Song, Congwen Tang, Pengfei Sun, Jiaxing Yang, Qianwu Hu, and Xiaoyan Zeng. "Microstructure and Wear of W-Particle-Reinforced Al Alloys Prepared by Laser Melt Injection." Micromachines 13, no. 5 (April 29, 2022): 699. http://dx.doi.org/10.3390/mi13050699.

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Анотація:

W-particle-reinforced Al alloys were prepared on a 7075 aluminum alloy surface via laser melt injection to improve their wear resistance, and the microstructure, microhardness, and wear resistance of the W/Al layers were studied. Scanning electron microscopy (SEM) results confirmed that a W/Al laser melting layer of about 1.5 mm thickness contained W particles, and Al4W was formed on the surface of the Al alloys. Due to the reinforcement of the W particles and good bonding of the W and Al matrix, the melting layer showed excellent wear resistance compared to that of Al alloys.

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37

Oyane, Ayako, Ikuko Sakamaki, Kenji Koga, and Maki Nakamura. "Formation of a Calcium Phosphate Layer with Immobilized Cobalt Chromite Nanoparticles on Cobalt−Chromium Alloy by a Laser-Assisted Biomimetic Process." Applied Sciences 10, no. 16 (August 12, 2020): 5584. http://dx.doi.org/10.3390/app10165584.

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The biocompatibility and osteoconductivity of metallic biomaterials can be achieved by calcium phosphate (CaP) coating. We recently developed a laser-assisted biomimetic (LAB) process for rapid and area-specific CaP coating on several materials. In the present study, the LAB process was applied to cobalt–chromium (Co−Cr) alloy, a metallic biomaterial widely used in orthopedic and dental applications. The LAB process was conducted by irradiation of unfocused pulsed laser light onto the substrate immersed in supersaturated CaP solution. The LAB-processed substrate formed CaP on the irradiated surface within only 5 min and was coated with a micron-thick CaP layer within 30 min by the effects of laser-induced surface modification and heating. Ultrastructural analysis with transmission electron microscopy revealed that the resultant CaP layer was integrated with the underlying substrate through two intermediate layers, an upper chromium oxide layer and a lower Co-rich (Cr-deficient) alloy layer. The CaP layer was loaded with a large number of cobalt chromite (CoCr2O4) nanoparticles. The results obtained offer new insights into the mechanism of CaP coating in the LAB process and future applications of LAB-processed Co−Cr alloys.

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38

Liu, Tongfang, Song Rui, and Sheng Li. "Layer-by-Layer Self-Assembly Composite Coatings for Improved Corrosion and Wear Resistance of Mg Alloy for Biomedical Applications." Coatings 11, no. 5 (April 27, 2021): 515. http://dx.doi.org/10.3390/coatings11050515.

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Mg alloys are promising biomedical metal due to their natural degradability, good processability, and favorable mechanical properties. However, the poor corrosion resistance limits their further clinical applications. In this study, the combined strategies of surface chemical treatment and layer-by-layer self-assembly were used to prepare composite coatings on Mg alloys to improve the biocorrosion resistance. Specially, alkalized AZ91 Mg alloy generated chemical linkage with silane via Si–O–Mg covalent bond at the interface. Subsequently, Si–OH group from silane formed a crosslinked silane layer by Si–O–Si network. Further chemical assembly with graphene oxide (GO), lengthened the diffusion pathway of corrosive medium. The chemically assembled composite coatings could firmly bond to Mg alloy substrate, which persistently and effectively acted as compact barriers against corrosion propagation. Improved biocorrosion resistance of AZ91 Mg alloy with self-assembly composite coatings of silane/GO was subsequently confirmed by immersion tests. Besides, the Mg alloy exhibited good wear resistance due to outside layer of GO with a lubricant effect. Cell viability of higher than 75% had also been found for the alloy with self-assembly composite coatings, which showed good cytocompatibility.

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39

Yang, Sheng, and Xian Qing Wan. "Microstructure Research of Magnesium with Laser Surface Cladding by Al-Si Alloy." Advanced Materials Research 291-294 (July 2011): 1369–72. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1369.

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Using laser clads magnesium surface with Al-Si eutectic powder, analyzing the organization and composition of the cladding layer with scanning electron microscopy and EDS. The results show that the cladding layer mainly composed of β (Mg17Al12) phase, α (Mg) + β (Mg17Al12) eutectic, α(Mg) solid solution, Mg2Si phase composition, and cladding layer and the substrate combined well, pores and cracks weren,t found. Laser heat treatment of the cladding layer, then the bulky Mg2Si phase was blown, small blocks were distributed in the grain boundary and improve the performance of the cladding layer.

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40

LotfiNeyestanak, Ali Akbar, and Saeed Daneshmand. "The Effect of Operational Cutting Parameters on Nitinol-60 in Wire Electrodischarge Machining." Advances in Materials Science and Engineering 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/457186.

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Shape memory alloys are a kind of active materials, which have significant characteristics in comparison with other alloys. Since these materials are applicable in different fields such as aerospace, automobile industry, medicine, and dentistry, the effects of wire electrodischarge machining on the properties of these alloys have been studied. In this paper, changes in the shape recovery ability and microhardness of the machined surface of Nitonol-60 shape memory alloy have been studied considering recasting and formation of resolidificated layer on the shape memory alloy surface. XRD and EDXA analyses of the surface layer of the sample besides a microscopic study of the shape memory alloy layer by SEM and a study of the changes in mechanical properties of the surface layer were done by performing microhardness and tension tests on the work piece surface. Considering the surface layer, reversible strain has been studied according to the shape recovery percentage of Nitinol-60 shape memory alloy. Results show that the surface layer formed on the surface of the samples has caused changes in both physical and mechanical properties of the cut surface because of the penetration of the separated materials in comparison with deeper layers of the piece.

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41

Zhou, X., Y. Younes, D. Wadeson, T. Hashimoto, and George E. Thompson. "Corrosion Control of Friction Stir Welded Aluminium Airframe Alloy." Advanced Materials Research 38 (March 2008): 298–305. http://dx.doi.org/10.4028/www.scientific.net/amr.38.298.

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In the present study, microstructure and its influence on corrosion behaviour of friction stir welded aluminium airframe alloy have been investigated. Further, the effect of laser surface treatment on the microstructure and the corrosion behaviour was also assessed. The welded AA2024 alloy showed the expected zones associated with friction stir welding. Corrosion testing showed that modified microstructure reduced its corrosion resistance to localized corrosion, with the regions immediately outside TMAZ being most susceptible to corrosion. Laser treatment resulted in a melted near-surface layer, up to 5 (m thick, where normal constituent particles are absent. Scrutiny of the melted near-surface layer revealed continuous segregation bands, approximately 10 nm thick, containing mainly copper. Corrosion testing showed that laser treatment increases the short term resistance to localized corrosion due to the removal constituent particles. However, prolonged testing revealed corrosion within the melted near-surface layer and delamination of the melted near-surface layer from underlying bulk alloy. The corrosion is associated with copper rich segregation bands that promote local microgalvanic action.

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42

Lee, Seong-Hee. "Microstructural Changes with Annealing of a Nanostructured Al Alloy Severely Plastic Deformed by Four-Layer Stack Accumulative Roll-Bonding Process." Journal of Nanoscience and Nanotechnology 20, no. 7 (July 1, 2020): 4419–22. http://dx.doi.org/10.1166/jnn.2020.17549.

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Microstructural changes with annealing of a nanostructured complex aluminum alloy fabricated by 3 cycles of four-layer stack ARB process using different Al alloys were investigated in detail. The four-layer stack ARB process using AA1050, AA5052 and AA6061 alloy sheets was performed up to 3 cycles without a lubricant at room temperature. The sample fabricated by the ARB is a multi-layer aluminum alloy sheet in which the AA1050, AA5052 and AA6061 aluminum alloys are alternately stacked to each other. The layer thickness of each alloy became thinner and elongated to the rolling direction with the number of ARB cycles. The grain size decreased with increasing of the number of ARB cycles, and became about 160 nm in thickness after 3 cycles. The complex Al alloy still showed ultrafine grained microstructure to annealing temperature of 300 °C, but it had a heterogeneous structure containing both the ultrafine grains and the coarse grains due to an occurrence of discontinuous recrystallization after 350 °C.

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43

Zhang, Dongqi, Jie Yu, Hui Li, Xin Zhou, Changhui Song, Chen Zhang, Shengnan Shen, Linqing Liu, and Chengyuan Dai. "Investigation of Laser Polishing of Four Selective Laser Melting Alloy Samples." Applied Sciences 10, no. 3 (January 21, 2020): 760. http://dx.doi.org/10.3390/app10030760.

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Анотація:

Selective laser melting (SLM) is a layer by layer process of melting and solidifying of metal powders. The surface quality of the previous layer directly affects the uniformity of the next layer. If the surface roughness value of the previous layer is large, there is the possibility of not being able to complete the layering process such that the entire process has to be abandoned. At least, it may result in long term durability problem and the inhomogeneity, may even make the processed structure not be able to be predicted. In the present study, the ability of a fiber laser to in-situ polish the rough surfaces of four typical additive-manufactured alloys, namely, Ti6Al4V, AlSi10Mg, 316L and IN718 was demonstrated. The results revealed that the surface roughness of the as-received alloys could be reduced to about 3 μm through the application of the laser-polishing process, and the initial surfaces had roughness values of 8.80–16.64 μm. Meanwhile, for a given energy density, a higher laser power produced a laser-polishing effect that was often more obvious, with the surface roughness decreasing with an increase in the laser power. Further, the polishing strategy will be optimized by simulation in our following study.

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44

Zhang, Yan Li. "Study on the Laser Alloy Cladding for Re-Manufacturing of the Surface of 40Cr." Applied Mechanics and Materials 713-715 (January 2015): 2900–2904. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.2900.

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Анотація:

The laser alloy cladding technology is used to treat the surface of 40Cr, and the two alloy powders are used separately. The process parameters are different, such as laser power, feed rate and scanning speed etc. The microstructure and hardness of cladding layers are analyzed by using scanning electron microscope and hardness tester. Generally, the surface quality is improved apparently. Under the similar laser power and powder quantity, the thickness of Ni60 cladding layer is much larger than Fe60. The hardness of Ni60 layer and Fe60 layer are all higher than substrate. There are more cracks in Ni60 layer than in Fe60 layer. The parameters of sample No.1 is optimal.

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45

Di, Jing, Jiani Yao, Meng Li, Shuo Zhou, Yuxian Wen, Haobin Sun, Hua Zhang, et al. "Research status of laser cladding material system on titanium alloy." Journal of Physics: Conference Series 2256, no. 1 (April 1, 2022): 012021. http://dx.doi.org/10.1088/1742-6596/2256/1/012021.

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Анотація:

Abstract Laser cladding technology is an advanced surface modification technology. By selecting different parameters and coating materials, the surface hardness and wear resistance of titanium alloys can be effectively improved. The cladding material is a key factor affecting the quality and performance of the cladding layer. Common cladding materials mainly include self-fluxing alloy powder, ceramic powder and rare earth element powder. This paper reviews the current research status of laser cladding material system on titanium alloy, and explains the problems that still need to be solved and puts forward the outlook.

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46

Wang, Ke Dian, Wen Qiang Duan, Xue Song Mei, and Wen Jun Wang. "Technology to Drill Micro-Holes without Recast Layer by Laser on Nickel-Based Alloy." Advanced Materials Research 459 (January 2012): 303–7. http://dx.doi.org/10.4028/www.scientific.net/amr.459.303.

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The technology to produce micro-holes without recast layer on nickel-based alloy is studied in this work. The holes are firstly drilled with Nd: YAG laser, a millisecond pulsed laser of high power and efficiency. For the reason of thermal effect, however, holes drilled by this laser always have the defect of recast layer, which is a serious problem, especially in the application as aviation and aerospace engine. In order to remove the recast layer, laser parameters are optimized to produce micro-holes with the least recast layer, and then a kind of chemical etching is used to clear the residual recast layer completely.

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47

Ye, Hong, Xiao Bin Zhang, Xia Chang, and Rui Chen. "Microstructures and Properties of Laser Al Alloying on AZ31 Magnesium Alloy." Advanced Materials Research 189-193 (February 2011): 867–70. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.867.

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In order to improve corrosion and wear resistance of magnesium alloy, Al coating was prepared on the AZ31 magnesium alloy by the thermal spraying, then the Al-rich layer was obtained by using a CO2 laser re-melting. The microstructures and phases of the alloying layer were analyzed by canning electron microscope (SEM) and X-ray diffraction apparatus (XRD). The mechanical properties were investigated by using hardness measurement and ring-on-flat apparatus. The corrosion behaviour was investigated in 3.5% (mass fraction) NaCl solution by electrochemical measurements. The results show that there are several different microstructures in the alloying layer, such as columnar, snowflake and network structure; the alloying layer consist of Mg2Al3, Mg17Al12 and α-Mg phases. The microhardness of alloy layer is about 170HV, higher than that of the AZ31 matrix (about 50HV). The wear tests show that the wear resistance of alloying layer is considerably improved comparing with the matrix. The potentiodynamic polarization results indicate that the corrosion resistance by laser alloying is enhanced.

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48

Yang, Jianyu, Xudong Li, Fei Li, Wenxiao Wang, Zhijie Li, Guanchao Li, and Hualong Xie. "Effect of Cooling Method on Formability of Laser Cladding IN718 Alloy." Materials 14, no. 13 (July 3, 2021): 3734. http://dx.doi.org/10.3390/ma14133734.

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Анотація:

The finite element model (FE) of temperature field of straight thin-walled samples in laser cladding IN718 was established, and the growth of microstructure was simulated by cellular automata (CA) method through macro-micro coupling (CA-FE). The effects of different cooling conditions on microstructure, hardness, and properties of laser-cladding layer were studied by designing cooling device. The results show that the simulation results are in good agreement with the microstructure of the cladding layer observed by the experiment. With the scanning strategy of reducing laser power layer-by-layer, the addition of water cooling device and the processing condition of 0.7 mm Z-axis lift, excellent thin-walled parts can be obtained. With the increase of cladding layers, the pool volume increases, the temperature value increases, the temperature gradient, cooling rate, solidification rate, K value gradually decrease, and eventually tend to be stable, in addition, the hardness shows a fluctuating downward trend. Under the processing conditions of layer-by-layer power reduction and water cooling device, the primary dendrite arm spacing reduced to about 8.3 μm, and the average hardness at the bottom of cladding layer increased from 260 HV to 288 HV. The yield strength and tensile strength of the tensile parts prepared under forced water cooling increased to a certain extent, while the elongation slightly decreased.

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49

Bryukhovetsky, V. V., V. V. Lytvynenko, D. E. Myla, V. A. Bychko, Yu F. Lonin, A. G. Ponomarev, and V. T. Uvarov. "Effect of Structural and Phase Changes under Relativistic Electron Pulsed Beam Irradiation on the Aluminum Alloys Micro-hardness." Physics and Chemistry of Solid State 22, no. 4 (November 11, 2021): 655–63. http://dx.doi.org/10.15330/pcss.22.4.655-663.

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The paper studies the distinctive features of micro-hardness value changes in the zone of industrial aluminum alloy 1933 and alloy 1380 irradiated by the relativistic electron beam. The surface layer was modified under the relativistic electron beam injected along with the equal energy parameters. However, we have to claim that some physical and technological properties of the irradiated alloys layer came with some differences. The modified layer micro-hardness increased over 30% in 1933 aluminum alloy and decreased by 10% in 1380 aluminum alloy. The mechanisms affecting the metal material strengthening transformation after a pulsed electron beam application are analyzed. Thus it was established that one of the core impacts to increase the micro-hardness of 1933 aluminum alloy surface layer was fine MgO impurities being absent in the initial alloy and caused by the irradiation, whilst the micro-hardness of the irradiated layer of the 1380 aluminum alloy decreases due to the dissolution during irradiation of the strengthening phases, which were identified in the initial state.

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50

Harada, Hideto, Shin Ichi Nishida, Mayumi Suzuki, Hisaki Watari, and T. Haga. "Direct Cladding from Molten Metals of Aluminum and Magnesium Alloys Using a Tandem Horizontal Twin Roll Caster." Applied Mechanics and Materials 772 (July 2015): 250–56. http://dx.doi.org/10.4028/www.scientific.net/amm.772.250.

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This paper describes direct cladding of magnesium (Mg) and aluminum (Al) alloys using a tandem horizontal twin roll caster that has three pairs of upper and lower rolls. Manufacturing conditions that are appropriate for fabricating Al/Mg and Al/Mg/Al cladded material were investigated. The surface condition of the cladded cast strip was examined. An electron probe micro analyzer was used to observe the interface between Al alloy and Mg alloy. The thickness of the mixed layer of Al and Mg alloy was 15μm, and how the materials were connected was clarified. Microscopic observation and backscattered electron analysis were used to investigate the cladding mechanisms of the Al and Mg alloy layers. Average hardness was determined using the Vickers hardness test at the Al layer and at the diffused layer between Mg and Al alloys. Cladding of Al/Mg alloy and A/Mg/Al alloy was possible using a tandem twin-roll caster. In addition, Al3Mg2 and Al12Mg17 phase precipitation at the interface of the Al and Mg alloys was confirmed during direct cladding from molten metals.

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