Готові списки джерел за темами / Joints de grains – Oxydation

Добірка наукової літератури з теми "Joints de grains – Oxydation"

Автор: Grafiati
Опубліковано: 3 червня 2022

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Статті в журналах з теми "Joints de grains – Oxydation"

1

Yao, Peng, Xiaoyan Li, Fengyang Jin, and Yang Li. "Morphology transformation on Cu3Sn grains during the formation of full Cu3Sn solder joints in electronic packaging." Soldering & Surface Mount Technology 30, no. 1 (February 5, 2018): 14–25. http://dx.doi.org/10.1108/ssmt-10-2017-0038.

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Анотація:
Purpose This paper aims to analyze the morphology transformation on the Cu3Sn grains during the formation of full Cu3Sn solder joints in electronic packaging. Design/methodology/approach Because of the infeasibility of analyzing the morphology transformation intuitively, a novel equivalent method is used. The morphology transformation on the Cu3Sn grains, during the formation of full Cu3Sn solder joints, is regarded as equivalent to the morphology transformation on the Cu3Sn grains derived from the Cu/Sn structures with different Sn thickness. Findings During soldering, the Cu3Sn grains first grew in the fine equiaxial shape in a ripening process until the critical size. Under the critical size, the Cu3Sn grains were changed from the equiaxial shape to the columnar shape. Moreover, the columnar Cu3Sn grains could be divided into different clusters with different growth directions. With the proceeding of soldering, the columnar Cu3Sn grains continued to grow in a feather of the width growing at a greater extent than the length. With the growth of the columnar Cu3Sn grains, adjacent Cu3Sn grains, within each cluster, merged with each other. Next, the merged columnar Cu3Sn grains, within each cluster, continued to merge with each other. Finally, the columnar Cu3Sn grains, within each cluster, merged into one coarse columnar Cu3Sn grain with the formation of full Cu3Sn solder joints. The detailed mechanism, for the very interesting morphology transformation, has been proposed. Originality/value Few researchers focused on the morphology transformation of interfacial phases during the formation of full intermetallic compounds joints. To bridge the research gap, the morphology transformation on the Cu3Sn grains during the formation of full Cu3Sn solder joints has been studied for the first time.
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2

Choi, Won Kyoung, Se-Young Jang, Jong Hoon Kim, Kyung-Wook Paik, and Hyuck Mo Lee. "Grain Morphology of Intermetallic Compounds at Solder Joints." Journal of Materials Research 17, no. 3 (March 2002): 597–99. http://dx.doi.org/10.1557/jmr.2002.0084.

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Анотація:
The grain morphology of the intermetallic compound (IMC) that forms at the interface between liquid solders and solid-metal substrates was observed at solder joints. Cu6Sn5 grains on Cu substrates were rough or rounded, and Ni3Sn4 grains on Ni substrates were faceted. Through the energy-based calculations, the relationship between the IMC grain morphology and Jackson's parameter α was explained. The Jackson's parameter of the IMC grain with a rough surface is smaller than 2 while it is larger than 2 for faceted grains.
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3

Lartigue, S., and L. Priester. "Étude des joints de grains dans l'alumine polycristalline." Matériaux & Techniques 73, no. 4-5 (1985): 163–69. http://dx.doi.org/10.1051/mattech/198573040163.

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4

Ding, Cheng Gang, Ya Qi Ni, Chuan Jun Guo, and Gao Feng Quan. "Study on Microstructure and Performance of Bonding-FSSW Hybrid Joints of AZ31 Magnesium Alloy." Advanced Materials Research 295-297 (July 2011): 1915–18. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.1915.

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Анотація:
In this paper a bonding-FSSW hybrid method is proposed and the performance and microstructure of bonding-FSSW joints of AZ31 aluminum alloy is examined . The results show that the bonding agent has little influence on the forming and mechanical property of FSSW nugget, the shear-resisting property of joints resulted from bonding with sealing glue and FSSW is equivalent to FSSW joints, in bonding-FSSW with high-strength bonding agent, the shear-resisting property of joints are apparently superior to that of pure FSSW or bonding joints. Tiny and uniform equiaxial grains are formed in the WN(Welding nugget zone) and coarse grains are formed in TMAZ (Thermomechanically affected zone) and HAZ (Heat affected zone), but with unequal size.
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5

Ding, Cheng Gang, Ya Qi Ni, Chuan Jun Guo, Gao Feng Quan, and Ji Ping Ge. "Study on Procedure of Bonding-FSSW Hybrid Joints of AZ31 Magnesium Alloy." Advanced Materials Research 314-316 (August 2011): 953–56. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.953.

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Анотація:
In this paper a bonding-FSSW hybrid method is proposed and the joining procedure as well as the microstructure and performance of bonding-FSSW hybrid joints of AZ31 aluminum alloy is examined . The results show that the bonding agent has little influence on the forming and mechanical property of FSSW nugget, the shear-resisting property of the hybrid joints with sealing glue is equivalent to FSSW joints, in bonding-FSSW hybrid joint with high-strength bonding agent, the shear-resisting property of joints are apparently superior to that of pure FSSW or bonding joints. Tiny and uniform equiaxial grains are formed in the WN(Welding nugget zone) and coarse grains are formed in TMAZ (Thermomechanically affected zone) and HAZ (Heat affected zone), but with unequal size. The good properties of the hybrid joints are obtained by choosing the optimal joining parameter.
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6

Zhang, Yongqiang, Xiangyi Xue, Jingli Zhang, Huiming Li, Ping Guo, Hao Pan, Hongmiao Hou, and Guoyu Jia. "Microstructure Control of Welded Joints of Dissimilar Titanium Alloys by Isothermal Forging." Materials 13, no. 15 (July 28, 2020): 3347. http://dx.doi.org/10.3390/ma13153347.

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Анотація:
In this study, the welded joints of dissimilar titanium alloys Ti600/Ti-22Al-25Nb were strengthened by isothermal forging. Different deformation parameters, including temperature, deformation speed, and reduction, were chosen. By isothermal forging, the original coarse dendritic grains of the welded joints were broken up effectively to form a large number of equiaxed grains. Meanwhile, many second phases were precipitated in the grain. Additionally, the dynamic globularization kinetics of second phases within the welded joints were quantitatively characterized and investigated. The results showed that the dynamic globularization kinetics and globularization rate were sensitive to the deformation conditions, and were promoted by a reduced strain rate and an elevated deformation temperature.
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7

Le Cloirec, P., P. Horny, and A. Ladousse. "Anaerobic Biological Removal of Dimethyldisulfide in a Chemical Process Wastewater." Water Science and Technology 26, no. 9-11 (November 1, 1992): 2069–72. http://dx.doi.org/10.2166/wst.1992.0663.

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Анотація:
The capability and performances of anaerobic biological removal of dimethyldisulfide were studied with a biofilter packed with a mixture of activated carbon and calcium carbonate grains. The oxygen sources of the bio-oxydation came from nitrates used like nutrients. The operating conditions (pH, volumetric load…) were determined. The quantification of the nutrients (DMDS, Nitrates) and by-products (Sulfates) in the influent and the effluent enabled us to approach the mechanisms of degradation of dimethyldisulfide.
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8

Seo, Sun-Kyoung, Moon Gi Cho та Hyuck Mo Lee. "Crystal orientation of β-Sn grain in Ni(P)/Sn–0.5Cu/Cu and Ni(P)/Sn–1.8Ag/Cu joints". Journal of Materials Research 25, № 10 (жовтень 2010): 1950–57. http://dx.doi.org/10.1557/jmr.2010.0253.

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Анотація:
Electron backscatter diffraction analysis was used to compare the crystal orientation of β-Sn grains in Ni(P)/Sn–0.5Cu/Cu and Ni(P)/Sn–1.8Ag/Cu joints before and after aging. In Ni(P)/solder/Cu joints, the solder composition (Cu versus Ag) significantly affects β-Sn grain orientation. In Ni(P)/Sn–0.5Cu/Cu, there are two types of small columnar grains grown from Ni(P) and Cu under bump metallurgy with a high-angle grain boundary crossing the joint closer to the Ni side; in contrast, Ni(P)/Sn–1.8Ag/Cu has large grains with low-angle boundaries. During thermal aging at 150 °C for 250 h, the Ni(P)/Sn–0.5Cu/Cu joints undergo a more significant microstructural change than the Ni(P)/Sn–1.8Ag/Cu joint. Additionally, obvious ledges developed along the high-angle grain boundary between the upper and lower areas in the Sn–0.5Cu joint.
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9

Yu, Si Rong, and Xian Jun Chen. "Microstructures and Properties of FSW Joints of AZ31B Mg Alloy." Advanced Materials Research 291-294 (July 2011): 855–59. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.855.

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Анотація:
The extruded AZ31B Mg alloy sheet was welded with friction stir welding. The microstructures and mechanical properties of the welded joint were investigated. The results show that the grains in the weld nugget zone were small, uniform and equiaxed. The grains in thermo-mechanical affected zone were stretched and relatively small, but were not as small and uniform as those in the weld nugget zone. The grains in the heat-affected zone were relatively coarse. The fracture of the welded joint occurred mainly in the heat affected zone. The tensile strength of the welded joints was up to 257.4 MPa and was 87.9% of the base material strength. The microhardness in the weld nugget zone was higher. The microhardness in the thermo-mechanical affected zone and heat affected zone were lower than that in the weld nugget zone. The microhardness in the weld nugget zone increased from the upper surface to the bottom.
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10

Guiraldenq, G. "Historique et évolution des recherches sur les joints de grains." Matériaux & Techniques 80, no. 6-7-8 (1992): 23–28. http://dx.doi.org/10.1051/mattech/199280060023.

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Більше джерел

Дисертації з теми "Joints de grains – Oxydation"

1

Marrouche, Abdelkhalek. "Caractérisation par microscopie électronique en transmission de joints de grains d'oxyde NiO formé par oxydation." Paris 11, 1985. http://www.theses.fr/1985PA112128.

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Анотація:
Cette thèse présente les résultats d'une étude statistique des caractéristiques géométriques des joints de grains dans l'oxyde NiO obtenu par oxydation thermique du nickel. Le travail comporte deux parties : La première est une étude critique des méthodes de détermination des caractéristiques géométriques des joints : relations d'orientation intercristalline, indice de coïncidence, critères de spécialité, plan du joint. La seconde partie concerne les résultats eux-mêmes, acquis à partir de l’analyse de 128 joints répartis entre 3 types d'échantillons bruts d'oxydation, ou recuits. Sur chaque échantillon, ont été examinées, la morphologie granulaire, la répartition et la densité des dislocations, la répartition entre joints et sous­joints, la texture d'oxydation, la distribution des relations d'orientation intergranulaire, la proportion de joints spéciaux. . . Il apparaît notamment que les joints parallèles à un plan {011} sont particulièrement instables et que la proportion de joints en relation de coïncidence est supérieure à celle qui existe dans un échantillon à distribution aléatoire
This thesis presents the results of a statistical study of the geometrical features of grain boundaries in nickel oxide NiO obtained by thermal oxidation of nickel. This work is divided into two parts: The first is a critical study of the methods used to determine the geometrical characteristics of the grain boundaries, orientation relationships, coincidence index, criteria of specialty, grain boundary plane. In the second part, we present the date of the study of 128 boundaries taken in 3 types of specimen resulting either from oxidation or additionally annealed. The following features were examined for each sample: granular morphology, distribution and density of dislocations, distribution of grain boundaries between subgrain boundaries and boundaries, oxidation texture, orientation relationships, "special" grain boundaries. It is shown in particular that boundaries parallel to a {011} plane are quite unstable and that the proportion of coincident boundaries is higher than that existing in a randomly distributed sample
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2

Yazidi, Samir. "Influence du caractère de spécialité des joints de grains sur la texture granulaire et la texture de joints dans l'oxyde de nickel." Paris 11, 1988. http://www.theses.fr/1988PA112155.

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Анотація:
Le but de cette étude est de déterminer si les propriétés intrinsèques des joints spéciaux et des joints généraux peuvent influencer des caractéristiques telles que la texture granulaire et la texture de joints au cours du grossissement granulaire dans un matériau polycristallin. Trois paramètres sont particulièrement importants :Le diamètre granulaire moyen, qui est l’indicateur de la force motrice résiduelle responsable du grossissement granulaire- la vitesse de croissance granulaire moyenne, puisque le critère de mobilité des joints est un facteur de discrimination du comportement des joints, et intègre l'influence des impuretés ;- le caractère de spécialité des joints, qui est le critère de classification des joints. Pour étudier l'influence des deux premiers paramètres, environ 250 joints, appartenant à plusieurs échantillons obtenus par oxydation de nickel dans diverses conditions ont été caractérisés. En l'état actuel des examens, les résultats ne semblent pas indiquer que le caractère de spécialité des joints affecte la texture granulaire ou la texture de joints d’une manière significative. Cette conclusion s'explique du tait des contraintes topologiques qui règnent dans un polycristal libre de contraintes externes
The purpose of this study is to verity whether the intrinsic properties of special and general grain boundaries (GB) may influence such characteristics as grain texture and grain boundary texture, during grain growth process in a polycristalline material. Three parameters are of importance: -average grain diameter which is an indicator of the residual driving force responsible for grain growth; -average grain growth rate, since GB mobility is a discriminative factor for special and general GB behavior and is a function of impurity conten; -specialness character Of the GB's which allows their classification. In order to examine the influence of the first two parameters, about 250 GB's belonging to several samples prepared by oxidation of nickel in various conditions, were characterized. The data which were obtained up to now do not seem to indicate that the specialness character of the, grain boundaries influences significantly grain texture or GB texture. This conclusion can be explained by topological requirements relative to a polycrystal tree of external stresses
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3

Poignant, Frédéric. "L'oxydation de céramiques à base de titanate de strontium semi-conducteur et la formation de barrières de potentiel aux joints de grains." Limoges, 1995. http://www.theses.fr/1995LIMO0015.

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Анотація:
Ce travail concerne principalement l'oxydation de ceramiques a base de srtio#3 dope par le niobium. Un leger exces de tio#2 favorise le frittage en presence d'une phase liquide. Ce traitement est realise sous atmosphere reductrice. Le materiau est semi-conducteur, les electrons de conduction etant fournis par le dopage et l'ionisation des lacunes d'oxygene. Les echantillons peuvent etre recuits en atmosphere oxydante entre 1000c et 1250c. Les v#o disparaissent par reaction en surface avec l'atmosphere environnante selon une cinetique caracterisee par thermogravimetrie. Leur elimination s'effectue par un processus de diffusion thermiquement active avec une energie 3. 0 0. 1 ev, valeur differente de celle observee pour l'oxydation de monocristaux (1 ev). Cette difference s'explique par l'enrichissement en v#s#r de la surface des grains au cours du frittage. L'evolution de la resistivite des echantillons pendant le traitement d'oxydation montre que la disparition des v#o s'accompagne de la formation de barrieres de potentiel aux joints de grains. Leur structure, complexe, est constituee d'une double barriere de schottky associee en serie avec une jonction i-n qui se developpe a l'interface entre la region superficielle compensee (nb#? 2v#/#/#s#r) et le grain semi-conducteur. L'etude des proprietes electrique a temperature ambiante permet encore d'estimer le coefficient de diffusion des v#s#r. Le caractere isolant des joints de grains a egalement ete obtenu par infiltration d'un melange fusible de bi#2o#3 et pbo. Les ceramiques impregnees ont ete soigneusement examinees en meb et en met. Les evolutions de leur resistivite pendant l'infiltration ont ete analysees et comparees a celles observees pour les echantillons oxydes. L'influence de l'heterogeneite microstructurale des ceramiques sur les proprietes electriques et la reponse dynamique des joints de grains est explicitee. Cinq niveaux de volume profonds, localises dans la bande interdite du semi-conducteur, sont detectes et caracterises par spectroscopie d'admittance
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4

Agrizzi, Ronqueti Larissa. "Study of grain boundary oxidation of high alloyed carbon steels at coiling temperature." Thesis, Compiègne, 2018. https://bibliotheque.utc.fr/Default/doc/SYRACUSE/2018COMP2405.

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Анотація:
Les aciers à haute résistance (AHSS) ont été largement utilisés dans le cadre d’applications automobiles visant à améliorer la sécurité et l’allègement des structures. Afin d'atteindre les objectifs en termes de propriétés mécaniques, ces nouveaux aciers sont composés de teneurs en éléments d’alliages beaucoup plus élevés (par exemple silicium et manganèse) que les aciers usuels. En conséquence, l'AHSS est susceptible de subir une oxydation interne sélective lors du refroidissement des bobines d’acier. L'oxydation sélective interne, en particulier l'oxydation aux joints de grains (GBO), est actuellement l'un des principaux obstacles à la production de ces aciers. Elle réduit le nombre de cycles avant la rupture de fatigue et rend ainsi difficile l’obtention des spécifications du client. Par conséquent, ce travail de thèse était axé sur l'effet de plusieurs paramètres sur le comportement à l’oxydation interne sélective. Parmi eux, l'impact de la décarburation, l'influence de la température de bobinage et de la couche de calamine, l'effet de différentes teneurs en silicium et / ou en manganèse et leur comportement en diffusion. De plus, l'impact de la désorientation des joints de grains sur l'oxydation interne a également été étudié. Des alliages modèles à base de fer binaires / ternaires ainsi que des aciers industriels ont été étudiés via un large ensemble de techniques expérimentales. Ces analyses ont mis en évidence une décarburation stable pour tous les échantillons étudiés qui n'a pas d'impact sur l'oxydation interne sélective pour une longue exposition aux conditions isothermes. Les profondeurs d’oxydation aux joints de grain ont été examinées selon les différentes configurations de tests et se sont révélées sensibles aux teneurs en silicium ou en manganèse. Pour certaines d'entre elles, différents comportements de diffusion du silicium ont été identifiés vis-à-vis de l'oxydation des joints de grains, en fonction des températures. Considérant quelques hypothèses restrictives, l'application de la théorie de l'oxydation interne sélective de Wagner a permis de déterminer le coefficient de diffusion de l'oxygène aux joints de grain. Pour surmonter certaines limites du modèle de Wagner, un modèle d'oxydation sélective a été appliqué pour comprendre l'effet de différents paramètres sur la pénétration de l'oxygène à l'intérieur du métal et principalement sur la profondeur des joints de grain affectée par l'oxydation sélective. Les connaissances acquises à partir de ce travail de thèse aideront à comprendre et à limiter l'oxydation sélective interne (principalement l’oxydation aux joints de grain) dans les aciers avec des compositions complexes en éléments d’alliage. En outre, les résultats peuvent être utilisés pour évaluer les paramètres d’un modèle d'oxydation sélective
Advanced high-strength steels (AHSS) have been widely used in automotive industry to improve safety and fuel economy. In order to reach the mechanical properties targets, these new steels are composed by much higher alloy contents (e.g. silicon and manganese) than usual steels. As consequence, the AHSS may suffer of selective internal oxidation during the cooling of hot coil. The selective internal oxidation, especially the grain boundary oxidation (GBO), is currently one of the main obstacles to the production of these steels. It reduces the number of cycles before fatigue failure and thus, makes it difficult to reach the specifications of the customer. Therefore, this PhD work was focused on the effect of several parameters on selective internal oxidation behavior. Among them, the impact of decarburization, the influence of coiling temperature and the mill scale, the effect of different silicon and/or manganese contents and their diffusion behavior. Moreover, the impact of grain boundary misorientation on grain boundary oxidation was also investigated. Either binary/ternary iron-based model alloys as well as industrial steels were investigated by a large set of experimental techniques. This analysis showed a stable decarburization for all investigated samples that does not impact the selective internal oxidation for long exposure time in isothermal conditions. The GBO depths were examined according to the different test configurations and were found dependent for some cases on silicon or manganese content. For some of them, different silicon diffusion behaviors were identified with regards to grain boundary oxidation depending on temperatures. Considering some restrictive hypotheses, the application of Wagner’s theory of selective internal oxidation allowed determining the grain boundary diffusion coefficient of oxygen. To overcome some limitations of Wagner’s model, a model of selective oxidation has been applied to understand the effect of different parameters on the penetration of oxygen inside the metal and principally on the grain boundary depth affected by selective oxidation. The knowledge acquired from this PhD work will help to understand and limit the selective internal oxidation (mainly GBO) in new steels with complex alloy compositions. Furthermore, the results may be used to assess a model of selective oxidation
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5

Chassagneux, Evelyne. "Corrosion du nickel en présence de V2O5." Phd thesis, Grenoble INPG, 1986. http://tel.archives-ouvertes.fr/tel-00845629.

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Анотація:
Les défauts d'un cristal sont les porteurs de la diffusion. Le flux J des défauts ponctuels dans le volume du cristal et le flux J' des espèces diffusant dans les défauts étendus sont supposés parallèles dans notre modèle d'oxydation des métaux. La vitesse s’écrit v = J(1 - théta ) + J'théta , théta est la portion de l'aire occupée par les "courts-circuit" constitués par les défauts étendus du cristal. Ce modèle permet d'expliquer le comportement d'échantillons de nickel revêtus de V₂O₅ sous oxygène pur, à 900°C : La vitesse d'oxydation est maximale pour une pression d'oxygène de 20 kPa et proportionnelle à l'épaisseur du dépôt. L'étude morphologique (par diffraction RX en incidence oblique, spectroscopie Auger, M. E. B. ) montre qu'un composé oxygéné de nickel et de vanadium est localisé dans la couche de l'oxyde NiO. Tant que ce composé est liquide ou non-stœchiométrique, la corrosion est catastrophique, sinon la diffusion est bloquée et la vitesse inférieure à celle observée pour le nickel pur. A priori, un élément susceptible de réagir avec V₂O₅ pour former un solide peut protéger le matériau. Ainsi un revêtement de magnésium métallique sur le nickel ou sur un acier inoxydable (type 25-20) s'avère efficace.
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6

Milanese, Julien. "Rupture intergranulaire assistée par l'oxydation et corrosion sous contrainte de produits minces en alliage 718 : rôle de la microstructure et de la chimie des joints de grains." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0054.

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Анотація:
Du fait de ses bonnes caractéristiques générales, l’alliage 718 est utilisé pour la fabrication de certains composants présents dans les assemblages combustibles des Réacteurs à Eau Pressurisée (REP). Malgré la relative résistance à l’amorçage de défauts de Corrosion Sous Contrainte (CSC) de cet alliage, l’amélioration recherchée de la fiabilité et de la sureté des installations nucléaires nécessite une compréhension approfondie de ce mécanisme d’endommagement et la mise en place de solutions industrielles visant à augmenter les marges de fonctionnement de ces composants. Ainsi, une modification de la gamme de fabrication est envisagée par Framatome afin d’accroitre la résistance à la CSC des composants en alliage 718. L’identification des effets de l’état métallurgique est essentielle afin d’appréhender le mécanisme de CSC et d’appuyer la solution industrielle retenue. Sur ce point, les effets de la précipitation de la phase et de l’écrouissage sur la sensibilité à la fissuration intergranulaire du matériau ont été étudiés et l’identification des mécanismes de déformation mis en jeu aux joints de grains entreprise. La précipitation de la phase et l’écrouissage se révèlent être bénéfiques et améliorent la résistance à l’amorçage de fissures intergranulaires de l’alliage 718. Néanmoins, il a été montré qu’ils ne permettaient pas la désensibilisation totale du matériau à eux seuls. En outre, une composante de déformation par glissement intergranulaire a été identifiée dans le cas de coulées d’alliage 718 sensibles à la fissuration intergranulaire, et est partiellement inhibée pour le matériau issu de la gamme de fabrication modifiée. Ces observations ont abouti à la proposition d’un mécanisme d’amorçage basé sur ce mode de déformation particulier. Les différents résultats obtenus constituent un apport considérable quant à la compréhension du mécanisme de CSC de l’alliage 718. Ils amènent également des éléments d’explication du bon comportement du matériau issu de la gamme de fabrication modifiée. Aussi les résultats d’essais visant à éprouver la résistance à l’endommagement du nouveau matériau, montrent toute la pertinence de la solution industrielle envisagée face à la problématique rencontrée
Due to its good resistance to Stress Corrosion Cracking (SCC), some of the components of nuclear assemblies of Pressurized Water Reactors (PWR) are made of alloy 718. Nevertheless, the current trend is increasing the liability and the safety of nuclear plants and needs a further understanding of the SCC mechanism of the material. Framatome is also considering a modification of the processing route of the strips used for the manufacturing of these components in order to improve the SCC resistance of the alloy 718. To better understand the SCC mechanism and support the solution undertaken, the influence of the metallurgical state on the damaging process must be investigated. The influences of the precipitation of phase and cold working on the susceptibility to intergranular cracking of the alloy were examined and the deformation mechanism at grain boundaries identified. It was shown that these two features were beneficial and improve the cracking resistance of the alloy but could not provide full desensitization when taken separately. Furthermore, grain boundary sliding was identified on the material susceptible to SCC whereas it is partially suppressed on the resistant one. From these observations, a mechanism for the initiation of intergranular cracks based on grain boundary sliding has been proposed. This work is a valuable contribution for the better understanding of the SCC mechanism of the alloy 718 and provides an explanation to the higher cracking resistance of the material derived from the new processing route. In addition, the relevance of the industrial solution to suit the problematic encountered was put forward
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MAGOARIEC, ALAIN. "Analyse par microscopie electronique a transmission de joints de graints et de defauts dans du silicium polycristallin soumis a une oxydation thermique." Caen, 1989. http://www.theses.fr/1989CAEN2029.

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Анотація:
Les diverses techniques de la microscopie electronique a transmission ont ete mises en uvre pour etudier les proprietes structurales du silicium polycristallin, materiau d'un usage croissant dans ses applications solaires et electroniques. Les procedes standard de reperage des directions cristallographiques, utilisant les angles d'inclinaison de la platine porte-objet sont generalement limites en precision. Une analyse fine des diagrammes de diffraction electronique, couplee a un traitement statistique des resultats, a permis de montrer que l'orientation relative de deux grains adjacents peut-etre determinee avec une incertitude d'une minute d'arc. Outre sa precision, cette technique presente l'interet d'etre adaptable sur un systeme informatique afin d'etre automatisee. L'oxydation thermique du silicium est une operation courante dans la fabrication des dispositifs. Nos observations sur deux types de materiaux mettent en evidence une forte relation entre la morphologie des interfaces et la qualite cristalline des substrats. Dans le volume des materiaux, une attention particuliere est portee a l'identification des defauts. Il ressort de ces experiences qu'a l'issue de recuit, les mecanismes de segregation et de precipitation des impuretes ne donnent pas d'effets observables dans des structures comportant une forte densite de macles (111)#3, (211)#3 et de defauts d'empilement
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8

M'rabat, Benyounes El. "Influence du phosphore sur la texture des joints de grains du fer et sur l'interaction dislocations de matrice-joints de grains." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb375998860.

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9

Elm'Rabat, Benyounès. "Influence du phosphore sur la texture des joints de grains du fer et sur l'interaction dislocations de matrice-joints de grains." Paris 11, 1986. http://www.theses.fr/1986PA112244.

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Анотація:
Analyse par microscopie électronique en transmission des effets du phosphore sur les joints de grains du fer pour tenter d'interpréter la fragilisation du fer par le phosphore en termes de formation et de relaxation des dislocations intrinsèques. Le phosphore entraine une augmentation du pourcentage des joints. Il semble favoriser la déformation à froid des joints dans lesquels un grand nombre de dislocations s'incorporent aisément. La température de "dispersion" ou "dislocation" des dislocations varie selon le type du joint et selon les caractéristiques de la dislocation. Analyse de l'interaction "dislocations-joints de grains" par étude de la déformation in situ des joints
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10

Mataveli, Suave Lorena. "High Temperature Durability of DS200+Hf Alloy." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0032/document.

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Анотація:
L'anisotropie de comportement mécanique du superalliage à solidification dirigée DS200+Hf et les mécanismes d'endommagement ont été étudiés entre 650°C et 1100°C. Des échantillons monogranulaires du même alliage ont été employés afin de mieux comprendre l'anisotropie de propriétés mécaniques et de durabilité. Des essais de traction, fluage, fatigue oligocylique, fatigue-fluage et de fissuration ont été réalisés, suivis d'observations au MEB afin d'analyser les modes d1endommagement.A 650°C, une forte anisotropie de durée de vie en fluage (et en fatigue) est observée alors que l'anisotropie est quasi inexistante à 1100°C en fluage. Ceci résulte de la mise en radeaux de la phase γ à haute température qui homogénéise la déformation, dégradation qui conduit à une augmentation de la vitesse de déformation en fatigue avec temps de maintien. Un amorçage intergranulaire a été observé pour tous les essais mécaniques en sens travers, notamment de par la présence de nombreux carbures aux joints des grains. Ces carbures sont les principaux sites d'amorçage de fissure de fatigue à 650°C et 900°C. A haute température (900°C), l'oxydation affecte non seulement l'amorçage en favorisant la fissuration des carbures de surface, mais elle affecte également la phase de propagation, via un processus combiné d'appauvrissement de la phase γ et d'émoussement de la pointe de fissure, le tout conduisant à un seuil de fissuration plus élevé. Sous vide, un tel processus n'est pas observé et les carbures ne sont plus les sites d'amorçage privilégiés. Lors de sollicitation de fluage en sens travers à basse température (750°C), les joints de grains fortement désorientés, avec un grain dans leur voisinage favorablement orienté pour le glissement simple et apte à la rotation cristalline, sont les plus critiques
The anisotropy in mechanical behavior of the directionally solidified DS200+Hf alloy and the damage mechanisms have been investigated between 650°C and1100°C. Single-crystalline specimens of the same alloy have also been used to get a better understanding of the anisotropy in mechanical properties and durability. Tension, creep, low-cycle fatigue (LCF), dwell-fatigue and crack propagation tests have been performed and analyzed by SEM observations to better understand the damage modes in this alloy. At 650°C, a considerable creep (and LCF) life anisotropy is observed while almost no anisotropy remains at 1100°C in creep. The γ rafting is mainly responsible for this decrease in creep anisotropy and for theincrease in creep rate in dwell-fatigue. An intergranular fracture mode has been observed for ail kind of solicitation along transverse direction, mainly due to the presence of grain boundary particles such as carbides. These carbides are also the main crack initiation sites in LCF at 650°C and at 900°C. At high temperature (900°C), oxidation not only controls the crack initiation mechanisms by inducing surface carbides cracking, but it also affects the crack propagation through a combined localized γ depletion and crack tip blunting, leading ove ra li to a higher crack propagation threshold. Such a behavior is not observed in high vacuum and surface carbides are no more the main crack initiation sites. lt is shown that at low temperature during transverse creep testing (750°C), highly misoriented grain boundaries, having one grain favorably oriented for single slip and lattice rotation, are the most critical ones
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Книги з теми "Joints de grains – Oxydation"

1

Ecole, d'été de métallurgie physique (1984 Carry-le-Rouet France). Les joints de grains dans les matériaux. Les Ulis, France: Editions de physique, 1985.

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2

Priester, Louisette. Les joints de grains. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8.

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3

Les joints de grains dans les materiaux. Editions de physique, 1985.

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4

Polycrystalline Semiconductors: Physical Properties and Applications. Springer-Verlag Berlin and Heidelberg GmbH & Co. KG, 1985.

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Частини книг з теми "Joints de grains – Oxydation"

1

Harashchenko, Olena, Vitaly Dmytryk, Viacheslav Berezutskyi, and Tetiana Syrenko. "Metallographic Determination of the Number and Sizes of Grains Depending on Structural and Phase Changes in the Metal of Welded Steam Pipe Joints." In Lecture Notes in Mechanical Engineering, 384–92. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-06025-0_38.

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2

"7 Grains, joints de grains et interfaces." In La microstructure des aciers et des fontes, 157–68. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0833-5-009.

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"7 Grains, joints de grains et interfaces." In La microstructure des aciers et des fontes, 157–68. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0833-5.c009.

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4

"Références." In Les joints de grains, 469–74. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-022.

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5

"Frontmatter." In Les joints de grains, i—ii. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-fm.

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6

"Chapitre 5 : Relaxation des contraintes intergranulaires." In Les joints de grains, 283–320. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-017.

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"Remerciements." In Les joints de grains, vii—viii. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-002.

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8

"Chapitre 4 : Ordre ou désordre à haute température ?" In Les joints de grains, 97–102. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-008.

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"Références." In Les joints de grains, 141–46. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-011.

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10

"Chapitre 4 : Interactions entre dislocations et joints de grains." In Les joints de grains, 255–82. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0241-8-016.

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Тези доповідей конференцій з теми "Joints de grains – Oxydation"

1

Gong, Jicheng, Changqing Liu, Paul P. Conway, and Vadim V. Silberschmidt. "Mechanical Behaviour of Grains in SnAgCu Solder Joints." In 2006 International Conference on Electronic Materials and Packaging. IEEE, 2006. http://dx.doi.org/10.1109/emap.2006.4430595.

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2

Priester, L. "Physico-chimie des joints de grains : ségrégation - précipitation." In PlastOx 2007 - Mécanismes et Mécanique des Interactions Plasticité - Environnement. Les Ulis, France: EDP Sciences, 2009. http://dx.doi.org/10.1051/ptox/2009006.

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3

Mondal, Debabrata, Abdullah Fahim, KM Rafidh Hassan, Jeffrey C. Suhling, and Pradeep Lall. "Deformation Behavior of SAC305 Solder Joints With Multiple Grains." In ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipack2020-2694.

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Abstract Lead-free solder joints are the most widely used interconnects in electronic packaging industries. Usually solder joints in most of the electronic devices are exposed to an environment where variation of temperature exists, which indicates cyclic thermal loading to be a very common type of external loading. Moreover, due to difference in the coefficient of thermal expansion (CTE) among dissimilar contact materials, shear stress develops in junctions under thermal loading, which significantly deteriorates the overall reliability. Hence, characterization of lead-free solder materials under thermal loading is essential to predict the performance and deformation behavior of joints in practical applications. A significant portion of the studies in this field are concerned with thermal loading of lead-free solder interconnects, each of which has a very small diameter, in sub-millimeter range. Although the solder balls have very small dimensions, most of the analyses considered them as a bulk material with homogeneous and isotropic properties. However, with the decrease of specimen dimensions, size effects and material directionality play a significant role in deformation mechanisms. Since a very few grains exist in a small specimen, individual grain properties play a vital role on overall material response. Therefore, modeling from the grain structure and orientation point of view could be an effective and more accurate way to predict solder joint deformation behavior under thermal loading. In this study, the effect of grain size and orientation of SAC305 is investigated for predicting anisotropic behavior of solder joints under thermal load. A simplified three-dimensional model of beach-ball configuration solder joint was generated and simulated using ABAQUS finite element (FE) software. Experimentally obtained directional properties such as elastic modulus and CTE were assigned to the computational geometry to create material anisotropy. The effects of material anisotropy were studied for varying grain size specimens, as well as for specimens with varying grain orientation.
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4

Priester, L. "Structures et défauts de structure des joints de grains." In PlastOx 2007 - Mécanismes et Mécanique des Interactions Plasticité - Environnement. Les Ulis, France: EDP Sciences, 2009. http://dx.doi.org/10.1051/ptox/2009005.

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5

Tanguy, D., and E. Vamvakopoulos. "Lacunes surabondantes dans les systèmes métal-hydrogène et endommagement des joints de grains : simulations atomiques." In PlastOx 2007 - Mécanismes et Mécanique des Interactions Plasticité - Environnement. Les Ulis, France: EDP Sciences, 2009. http://dx.doi.org/10.1051/ptox/2009007.

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6

Holdermann, Ken, Gayatri Cuddalorepatta, and Abhijit Dasgupta. "Dynamic Recrystallization of Sn3.0Ag0.5Cu Pb-Free Solder Alloy." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67671.

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Анотація:
This study examines microstructural recrystallization in Sn3.0Ag0.5Cu (SAC305) solder joints due to isothermal, mechanical cycling. It is well known that after reflow SAC solder joints at length scales of 200 μm consist of only a few grains [1–3]. This coarse microstructure makes the joint mechanically inhomogeneous and anisotropic, and non-repeatable. Creep tests conducted on modified lap-shear SAC305 solder joints therefore show significant scatter in their results, because of piece-to-piece variability in the microstructural morphology [1]. However, results of cyclic fatigue tests of the same SAC305 solder joints show less significant scatter [4]. One possible hypothesis is that dynamic recrystallization occurs during the cycling, resulting in a much finer (and hence more isotropic, homogeneous and repeatable) microstructure. Recrystallization of solder has been reported to occur under thermal cycling [5–6]. The objective of this study is to assess the extent of recrystallization of SAC305 solder during isothermal mechanical cycling fatigue. Focused ion beam technology is used to prepare a very clean and even surface to reveal the SAC305 grains in modified lap-shear test specimens, both before and after isothermal mechanical cycling. Polarized light microscopy, scanning electron microscopy and focused ion beam microscopy are used to reveal the microstructure of these SAC305 solder joints. The results show that mechanical cycling produces the same type of recrystallization behavior of SAC solder, as has been reported in the literature for thermally cycled specimens [5–6]. The number of grains in the SAC305 solder joint changes from a few to hundreds, during mechanical cycling. As expected, the recrystallization is observed to be localized around cracks in the solder joint, where the local stresses are the highest. The minimal grain size near the cracked region is approximately 4–6 μm and the average grain size increases significantly with increasing distance from the crack face. The transition of solder from very few (non-homogeneous and anisotropic) to a homogenous recrystallized state may be one possible explanation for differences in the extent of scatter in the data from creep tests and isothermal mechanical fatigue tests.
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7

Fahim, Abdullah, Sudan Ahmed, Jeffrey C. Suhling, and Pradeep Lall. "Nanoindentation Measurements of the Mechanical Properties of Individual Phases Within Lead Free Solder Joints Subjected to Isothermal Aging." In ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipack2018-8408.

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Exposure of lead free solder joints to high temperature isothermal aging conditions leads to microstructure evolution, which mainly includes coarsening of the intermetallic (IMC) phases. In our previous work, it was found that the coarsening of IMCs led to degradation of the overall mechanical properties of the SAC solder composite consisting of β-Sn matrix and IMC particles. However, it is not known whether the isothermal aging changes properties of the individual β-Sn and IMC phases, which could also be affecting to the overall degradation of properties. In this study, the aging induced variations of the mechanical properties of the β-Sn phase, and of Sn-Cu IMC particles in SAC solder joints have been explored using nanoindentation. SAC solder joints extracted from SuperBGA (SBGA) packages were aged for different time intervals (0, 1, 5, 10 days) at T = 125 °C. Nanoindentation test samples were prepared by cross sectioning the solder joints, and then molding them in epoxy and polishing them to prepare the joint surfaces for nanoindentation. Multiple β-Sn grains were identified in joints using optical polarized microscopy and IMCs were also observed. Individual β-Sn grains and IMC particles were then indented at room temperature to measure their mechanical properties (elastic modulus and hardness) and time dependent creep deformations. Properties measured at different aging time were then compared to explore aging induced degradations of the individual phases. The properties of the individual phases did not show significant degradation. Thus, IMC coarsening is the primary reason for the degradation of bulk solder joint properties, and changes of the properties of the individual phases making up the lead free solder material are negligible.
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8

Hoque, Mohd Aminul, Mohammad Ashraful Haq, Jeffrey C. Suhling, and Pradeep Lall. "Study of Lead Free Solder Joints Subjected to Isothermal Mechanical Shear Cycling." In ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipack2020-2692.

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Abstract Electronic packages are usually subjected to varying temperature conditions, thus subjecting the package to thermal cyclic loadings. As the different components of the package are made up of materials of different Coefficients of Thermal Expansion (CTE), the thermal cyclic loading brings about fluctuating shear stress to arise within the package, ultimately leading to its failure. It has been seen in previous literature that the recrystallization assisted cracking is a major factor that leads to the failure of solder joints when subjected to thermomechanical cycles. In this study, the authors have tried to determine whether the mechanical shear cycling of aged and non-aged samples of SAC305 lead free solder joints undergo a recrystallization phase before its ultimate failure. Arrays (3 × 3) of SAC305 solder joints of roughly 750μm in diameter were reflowed in between two FR-4 printed circuit boards to create a sandwiched structural sample. The samples were then polished to expose the solder joints. A polarized light microscope was utilized to capture the images of the joints before and after the mechanical cycling and analyzed to observe any changes in the microstructure in the form of recrystallization of the tin grains.
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9

Park, Seungbae, Ramji Dhakal, Lawrence Lehman, and Eric Cotts. "Grain Formation and Intergrain Stresses in a Sn-Ag-Cu Solder Ball." In ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems collocated with the ASME 2005 Heat Transfer Summer Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/ipack2005-73058.

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The thermo-mechanical behavior of near eutectic lead-free SnAgCu (SAC) solder joints under Deep Thermal Cycling (DTC) and in-situ thermal loading was examined. Crossed polarizer, optical microscopy revealed that in ball grid array (BGA) solder joints, these Sn rich, Pb-free solders exhibit large grained Sn structures. After imaging, these SnAgCu solder joints were subjected to repeated thermal stresses under an inert atmosphere. Subsequent to this thermal loading, the samples were again examined with optical microscopy. Using both data sets, the intergrain strains and deformations were quantified by Digital image correlation, a full field optical measurement technique. The relations between the positions of grains as well as intermetallics compounds, their boundaries and Sn deformation fields were examined.
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10

Togasaki, Yu, Takashi Honda, Tetsuya Sasaki, Atsushi Yamaguchi, and Hirokazu Tsuji. "Effect of Ultrasonic Impact Treatment on Fatigue Life in Butt Welded Joints of Austenitic Stainless Steel." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25539.

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Ultrasonic impact treatment (UIT), which is a type of peening method, is usually used as a post-weld treatment for mild steel in order to improve the fatigue strength of its welded joints. As there is insufficient fatigue data available on welded joints of austenitic stainless steel treated by UIT, the authors decide to conduct fatigue tests on butt welded joints of austenitic stainless steel treated by UIT. The results were compared with the fatigue lives of as-weld joints to investigate the effect of UIT on the fatigue lives of welded joints of austenitic stainless steel. The fatigue lives of butt welded joints treated by UIT were more than 1.5 times longer than those of as-weld joints. The following were considered as possible reasons for this improvement in fatigue life: change in residual stress near the weld toes, relaxation of stress concentration at the weld toes, and refinement of grains under the weld toes. The residual stress measured near the weld toes by using the X-ray diffraction method was transformed from tension to compression by the application of UIT. The stress concentration factors at the welded toes were reduced about 10% by the application of UIT.
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