Rozprawy doktorskie na temat „Transition Metal Based Intermetallic Alloys”

Le but de ce travail est d'étudier expérimentalement l'élaboration des poudres de Ni3Al par mécanosynthèse ainsi que le comportement du produit broyé en fonction de la composition initiale, des conditions et de la durée d'élaboration. L'influence du désordre chimique sur le processus d'amorphisation des métaux à l'état solide est envisagée. Une étude bibliographique, présentée au premier chapitre, a permis de cerner, en partie, les phénomènes conduisant à l'activation des solides par broyage. Pour cela des expériences préliminaires sont effectuées, en deuxième partie, sur un composé modèle (Ni10Zr7) pour déterminer le rôle fondamental des conditions de broyage correspondant aux vitesses des éléments de rotation du dispositif utilisé. Après une étude comparative de deux dispositifs différents, la caractérisation des produits montre que les transformations de phase souhaitées correspondent à des conditions déterminées. Dans la troisième partie, et pour les mêmes conditions de broyage, une étude cinétique est consacrée au comportement, au cours de l'élaboration, d'un mélange de poudres élémentaires de Ni et Al et aussi de ruban de Ni3Al. L'influence d'un agent de contrôle pour prévenir le soudage des produits broyés est aussi considérée. Une similitude dans le comportement des poudres élémentaires et de rubans, après des durées élevées pour certaines conditions de broyage, est établie. Les aspects majeurs relevés dans cette étude sont : la détermination des conditions équivalentes de broyage ; le désordre chimique précède la transition de la phase cristalline à celle amorphe et enfin l'impossibilité de la formation d'une phase complètement ou même majoritairement amorphe à partir du mélange de poudres élémentaires (Al et Ni) et de l'intermétallique (Ni3Al) comme dans le cas de Ni10Zr7

Secondary Al-Si-Cu-Mg based foundry alloys are widely used in automotive industry to particularly produce powertrain cast components mainly due to their good ratio between weight and mechanical properties, and excellent casting characteristics. Presence of impurity elements, such as Fe, Mn, Cr, Ti, V and Zr, in secondary Al-Si alloys is one of the critical issues since these elements tend to reduce alloy mechanical properties. There is an ongoing effort to control the formation of intermetallic phases containing transition metals, during alloy solidification. Although phases formation involving these transition metal impurities in non-grain-refined Al-Si alloys is well documented in the literature, the role of grain refinement in microstructural evolution of secondary Al-Si-Cu-Mg alloys needs further experimental investigations since chemical grain refinement is one of the critical melt treatment operations in foundries. The primary aim of this PhD work is thus defined to characterize the formation of intermetallic phases containing transition metals in secondary Al-7Si-3Cu-0.3Mg alloy before and after grain refinement by different master alloys and contribute to the understanding of the mechanisms underlying the microstructural changes occurring with the addition of grain refiner. Another critical issue related to Al-Si-Cu-Mg alloys is their limited thermal stability at temperatures above 200 oC. The operating temperature in engine combustion chamber is reported to often exceed 200 oC during service. Moreover, a further increase of operating temperature is anticipated due to the expected engine power enhancement in near future, which indicates the necessity for the development of a new creep-resistant Al alloys. Deliberate addition of transition metals is believed to yield a new heat-resistant alloy by promoting the formation of thermally stable dispersoids inside α-Al grains. This study thus also attempted to investigate the effect of adding transition metals Zr, V and Ni on the solidification processing, microstructural evolution and room/high-temperature tensile properties of secondary Al-7Si-3Cu-0.3Mg alloy, one of the most used alloys in automotive engine manufacturing. The influence of transition metal impurities on microstructural evolution of secondary Al-7Si-3Cu-0.3Mg alloy was investigated before and after chemical treatment with different master alloys: Al-10Sr, Al-5Ti-1B, Al-10Ti and Al-5B. The Al-10Zr, Al-10V and Al-25Ni master alloys were used for the experimental investigations of the effects of deliberate additions of transition metals on the solidification path, microstructure and mechanical properties of secondary Al-7Si-3Cu-0.3Mg alloy. Solidification path of the alloys was characterized by the traditional thermal analysis technique and differential scanning calorimetry (DSC). Optical microscope (OM), scanning electron microscope (SEM) equipped with energy-dispersive (EDS), wavelength-dispersive spectrometers (WDS) and electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) equipped with EDS were used to characterize the type, morphology and distribution of the phases precipitated during solidification and heat treatment of the studied alloys. The static tensile properties of the alloys were characterized at room (20 oC) and high temperatures (200 and 300 ºC). Experimental findings indicate that the Sr-modification and grain refinement of secondary Al-7Si-3Cu-0.3Mg alloy with Al-Ti-B can be enough effective despite the presence of transition metal impurities in the material and the variation of pouring temperature. However, the V and Zr (~100 ppm each) available in secondary Al-7Si-3Cu-0.3Mg alloy tended to promote the precipitation of harmful, primary AlSiTi intermetallics during solidification of grain-refined alloy. This implies that more effective optimization of grain refiner addition level in secondary Al foundry alloys can be achieved by considering the role of transition metal impurities, Ti, V and Zr, since the formation of primary AlSiTi particles causes (1) the depletion of Ti needed for effective α-Al grains growth restriction and (2) the formation of casting defects, such as shrinkage, due to their flaky morphology. Iron available in secondary Al-7Si-3Cu-0.3Mg alloy as impurity only formed more desirable α-Al15(FeMn)3Si2 phase in non-grain refined state. After grain refinement by Al-5Ti-1B, Fe was also involved in the formation of more deleterious β-Al5FeSi phase. The TiB2 particles acted as nucleation site for β-Al5FeSi phase. Both higher cooling rate and higher Al-5Ti-1B addition levels tended to promote the formation of deleterious β-Al5FeSi at the expense of α-Al15(FeMn)3Si2 in the alloy refined by Al-5Ti-1B. This implies that rather than the ratio between Mn and Fe, the nucleation kinetics of Fe-rich intermetallics play a decisive role in the selection of competing α-Al15(FeMn)3Si2 and β-Al5FeSi intermetallic phases for the precipitation during alloy solidification. Moreover, grain refinement of secondary Al-7Si-3Cu-0.3Mg alloy by Al-5B showed comparable performance to that of Al-5Ti-1B master alloy, however, without any deleterious influence on the precipitation sequence of Fe-rich phases, i.e. deleterious β-Al5FeSi reaction remained unfavourable during alloy solidification. Experimental findings from the investigations of the effect of deliberate Zr and V addition revealed that Zr and V addition can induce the grain refinement of secondary Al-7Si-3Cu-0.3Mg alloy. While Zr addition yielded the formation of pro-peritectic Zr-rich particles, which are found to nucleate primary α-Al at low undercooling, the effect of adding V can be characterized by the enhancement of the degree of constitutional undercooling. Combined Zr and V addition showed more effective grain refinement level than their individual additions. Majority of both Zr and V added to the alloy were retained inside α-Al matrix during solidification. As a result, limited amounts of Zr and V were rejected to the interdendritic liquid by the growing α-Al dendrites, then forming small-sized and rarely distributed intermetallics. Owing to its low solid solubility in α-Al, nickel available as impurity (~ 200 ppm) or after deliberate addition (0.25 wt.%) in secondary Al-7Si-3Cu-0.3Mg alloy was mainly bound to interdendritic, insoluble intermetallics, such as Al6Cu3Ni and Al9(FeCu)Ni phases. The presence of ~ 200 ppm Ni was sufficient to diminish to a certain extent the precipitation hardening effect of Cu. Interdendritic Zr/V/Ni-rich phases remained undissolved into the α-Al matrix during solution heat treatment. Therefore, the supersaturated transition metals in α-Al solid solution obtained during solidification was only involved in the solid-state precipitation occurring during heat treatment. Unlike Cu/Mg-rich strengthening precipitates that commonly form during aging, the Zr/V-rich precipitates tended to form during solution heat treatment. Other transition metals, such as Mn, Fe, Cr and Ti, which were present as impurities in secondary Al-7Si-3Cu-0.3Mg alloy significantly promoted the formation of nano-sized Zr/V-rich precipitates inside α-Al grains. These thermally more stable precipitates, including novel α-Al(MnVFe)Si, were credited for the enhanced high-temperature strength properties of Al-7Si-3Cu-0.3Mg alloy by ~ 20 %.
Secondary Al-Si-Cu-Mg based foundry alloys are widely used in automotive industry to particularly produce powertrain cast components mainly due to their good ratio between weight and mechanical properties, and excellent casting characteristics. Presence of impurity elements, such as Fe, Mn, Cr, Ti, V and Zr, in secondary Al-Si alloys is one of the critical issues since these elements tend to reduce alloy mechanical properties. There is an ongoing effort to control the formation of intermetallic phases containing transition metals, during alloy solidification. Although phases formation involving these transition metal impurities in non-grain-refined Al-Si alloys is well documented in the literature, the role of grain refinement in microstructural evolution of secondary Al-Si-Cu-Mg alloys needs further experimental investigations since chemical grain refinement is one of the critical melt treatment operations in foundries. The primary aim of this PhD work is thus defined to characterize the formation of intermetallic phases containing transition metals in secondary Al-7Si-3Cu-0.3Mg alloy before and after grain refinement by different master alloys and contribute to the understanding of the mechanisms underlying the microstructural changes occurring with the addition of grain refiner. Another critical issue related to Al-Si-Cu-Mg alloys is their limited thermal stability at temperatures above 200 oC. The operating temperature in engine combustion chamber is reported to often exceed 200 oC during service. Moreover, a further increase of operating temperature is anticipated due to the expected engine power enhancement in near future, which indicates the necessity for the development of a new creep-resistant Al alloys. Deliberate addition of transition metals is believed to yield a new heat-resistant alloy by promoting the formation of thermally stable dispersoids inside α-Al grains. This study thus also attempted to investigate the effect of adding transition metals Zr, V and Ni on the solidification processing, microstructural evolution and room/high-temperature tensile properties of secondary Al-7Si-3Cu-0.3Mg alloy, one of the most used alloys in automotive engine manufacturing. The influence of transition metal impurities on microstructural evolution of secondary Al-7Si-3Cu-0.3Mg alloy was investigated before and after chemical treatment with different master alloys: Al-10Sr, Al-5Ti-1B, Al-10Ti and Al-5B. The Al-10Zr, Al-10V and Al-25Ni master alloys were used for the experimental investigations of the effects of deliberate additions of transition metals on the solidification path, microstructure and mechanical properties of secondary Al-7Si-3Cu-0.3Mg alloy. Solidification path of the alloys was characterized by the traditional thermal analysis technique and differential scanning calorimetry (DSC). Optical microscope (OM), scanning electron microscope (SEM) equipped with energy-dispersive (EDS), wavelength-dispersive spectrometers (WDS) and electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) equipped with EDS were used to characterize the type, morphology and distribution of the phases precipitated during solidification and heat treatment of the studied alloys. The static tensile properties of the alloys were characterized at room (20 oC) and high temperatures (200 and 300 ºC). Experimental findings indicate that the Sr-modification and grain refinement of secondary Al-7Si-3Cu-0.3Mg alloy with Al-Ti-B can be enough effective despite the presence of transition metal impurities in the material and the variation of pouring temperature. However, the V and Zr (~100 ppm each) available in secondary Al-7Si-3Cu-0.3Mg alloy tended to promote the precipitation of harmful, primary AlSiTi intermetallics during solidification of grain-refined alloy. This implies that more effective optimization of grain refiner addition level in secondary Al foundry alloys can be achieved by considering the role of transition metal impurities, Ti, V and Zr, since the formation of primary AlSiTi particles causes (1) the depletion of Ti needed for effective α-Al grains growth restriction and (2) the formation of casting defects, such as shrinkage, due to their flaky morphology. Iron available in secondary Al-7Si-3Cu-0.3Mg alloy as impurity only formed more desirable α-Al15(FeMn)3Si2 phase in non-grain refined state. After grain refinement by Al-5Ti-1B, Fe was also involved in the formation of more deleterious β-Al5FeSi phase. The TiB2 particles acted as nucleation site for β-Al5FeSi phase. Both higher cooling rate and higher Al-5Ti-1B addition levels tended to promote the formation of deleterious β-Al5FeSi at the expense of α-Al15(FeMn)3Si2 in the alloy refined by Al-5Ti-1B. This implies that rather than the ratio between Mn and Fe, the nucleation kinetics of Fe-rich intermetallics play a decisive role in the selection of competing α-Al15(FeMn)3Si2 and β-Al5FeSi intermetallic phases for the precipitation during alloy solidification. Moreover, grain refinement of secondary Al-7Si-3Cu-0.3Mg alloy by Al-5B showed comparable performance to that of Al-5Ti-1B master alloy, however, without any deleterious influence on the precipitation sequence of Fe-rich phases, i.e. deleterious β-Al5FeSi reaction remained unfavourable during alloy solidification. Experimental findings from the investigations of the effect of deliberate Zr and V addition revealed that Zr and V addition can induce the grain refinement of secondary Al-7Si-3Cu-0.3Mg alloy. While Zr addition yielded the formation of pro-peritectic Zr-rich particles, which are found to nucleate primary α-Al at low undercooling, the effect of adding V can be characterized by the enhancement of the degree of constitutional undercooling. Combined Zr and V addition showed more effective grain refinement level than their individual additions. Majority of both Zr and V added to the alloy were retained inside α-Al matrix during solidification. As a result, limited amounts of Zr and V were rejected to the interdendritic liquid by the growing α-Al dendrites, then forming small-sized and rarely distributed intermetallics. Owing to its low solid solubility in α-Al, nickel available as impurity (~ 200 ppm) or after deliberate addition (0.25 wt.%) in secondary Al-7Si-3Cu-0.3Mg alloy was mainly bound to interdendritic, insoluble intermetallics, such as Al6Cu3Ni and Al9(FeCu)Ni phases. The presence of ~ 200 ppm Ni was sufficient to diminish to a certain extent the precipitation hardening effect of Cu. Interdendritic Zr/V/Ni-rich phases remained undissolved into the α-Al matrix during solution heat treatment. Therefore, the supersaturated transition metals in α-Al solid solution obtained during solidification was only involved in the solid-state precipitation occurring during heat treatment. Unlike Cu/Mg-rich strengthening precipitates that commonly form during aging, the Zr/V-rich precipitates tended to form during solution heat treatment. Other transition metals, such as Mn, Fe, Cr and Ti, which were present as impurities in secondary Al-7Si-3Cu-0.3Mg alloy significantly promoted the formation of nano-sized Zr/V-rich precipitates inside α-Al grains. These thermally more stable precipitates, including novel α-Al(MnVFe)Si, were credited for the enhanced high-temperature strength properties of Al-7Si-3Cu-0.3Mg alloy by ~ 20 %.

Nous presentons dans la premiere partie les avantages d'une fusion en levitation pour la preparation de composes intermetalliques terres rares-metaux de transition destines, a l'etude du magnetisme itinerant. Viennent ensuite les caracteristiques techniques du four a levitation que nous avons realise puis des exemples d'applications d'un tel procede d'elaboration. Dans la seconde partie, nous contribuons a l'etude de l'antiferromagnetisme de bande proche de l'instabilite a travers certaines phases de laves rmn#2. Grace aux informations experimentales sur les interactions d'echange extraites des diagrammes de diffraction neutronique et sur l'anisotropie, apprehendee a partir de spectres de resonance magnetique nucleaire, nous proposons un nouvel arrangement des moments magnetiques des atomes de manganese au sein de la structure magnetique du compose ymn#2. Nous discutons des effets de la frustration des interactions d'echange et de la forte anisotropie du manganese dans ce compose. Nous etudions egalement les proprietes magnetiques des composes pseudo-binaires y#1##xtb#xmn#2: la substitution d'atomes de terbium a ceux d'yttrium introduit, en sus de la tres forte frustration des interactions d'echange qui existent deja dans le compose ymn#2, une competition des energies d'anisotropie du terbium et du manganese. Il en resulte un ordre magnetique homogene complexe ainsi que l'apparition d'un ordre a courte distance que nous avons plus particulierement etudie dans le compose tbmn#2. Le terbium joue dans ce cas, le role d'une sonde des correlations de densite d'aimantation du manganese

Etude des composes intermetalliques cecusi, cezn::(5), ceal::(2)ga::(2) et plus particulierement cept::(2)si::(2). Cecusi s'ordonne ferromagnetiquement en dessous de 15,5 k. Les composes de cezn::(5) et ceal::(2)ga::(2) sont des reseaux de kondo presentant une structure antiferromagnetique en dessous de 3,8k et 8,5k respectivement. Description de leur structure magnetique a l'aide d'un vecteur de propagation. Cept::(2)si::(2) est un compose tetragonal de type reseau de kondo non magnetique. Analyse des trois regimes de temperature des proprietes magnetiques. Ce compose est situe entre les fermions lourds et les valences intermediaires

Analyse phénoménologique des processus d'aimantation des composes YCo5 et GDCo5 mettant en évidence une anisotropie des interactions d'échangé Ln-Co liée à l'anisotropie de polarisation des électrons 5d de l'atome Ln. Etude de l'incidence de l'instabilité du magnétisme de bande 3d sur l'anisotropie magnétique dans les phases Ln2Co7 et LnCo3. Etude de l'anisotropie des systèmes à empilement quasi-unidimensionnel LnCo(1-epsilon ). Analyse de la sélection orbitale induite par les intégrales de transfert

Etude du phénomène de valence intermédiaire dans les composés du type CeM2Si2 (m=métal de transition 3d). Mise en évidence d'anomalies lors de l'absorption x ainsi que dans les propriétés magnétiques et de transport. Mesure des seuils d'absorption l(i)ii et classification des composes sur une échelle de valeurs de la valence. Etude des variations thermiques de la valence. L'instabilité de valence a également été mise en évidence qualitativement par des mesures des paramètres de maille.

Etude realisee pour les hydrures cristallins zr#2nih#x (x=2, 1; 3 et 4) et amorphes (x=2,5 et 4,5). On obtient les parametres du diffusion en mesurant la constante de relaxation quadripolaire des spins nucleaires entre 170 k et 470 k. On propose un mecanisme de sauts des atomes d'hydrogene

Etude detaillee de l'evolution de la structure fine des dislocations dans une large gamme de temperature autour du pic de limite elastique (600-700c). Analyse cristallographique de la structure ordonnee l1::(2) et des defauts plans de cette structure. Presentation, a partir de cette analyse, des resultats des simulations atomiques de paroi d'antiphase. Calcul de forme et d'energie de dislocations en elasticite anisotrope. Analyse du mecanisme de formation des defauts d'empilement. Etude, en fonction de la temperature d'essai, de la structure fine des dislocations. Influence d'une variation de composition sur la morphologie des dislocations

by Kwok Chi-Kong = 氧化鋁及鋁-鈦金屬間化合物增強的鋁基複合物的製造和表徵 / 郭智江.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Kwok Chi-Kong = Yang hua lv ji lü-tai jin shu jian hua he wu zeng qiang de lü ji fu he wu de zhi zao he biao zheng / Guo Zhijiang.
Acknowledgement --- p.i
Abstract --- p.ii
摘要 --- p.iv
List of tables --- p.v
List of figures --- p.vi
Table of contents --- p.ix
Chapter Chapter 1 --- Introduction --- p.1-1
Chapter 1.1. --- Metal matrix composites (MMCs) --- p.1-1
Chapter 1.1.1. --- Introduction --- p.1-1
Chapter 1.1.2. --- Reinforcements in metal-matrix composites --- p.1-1
Chapter 1.1.3. --- Interface between matrix and reinforcements --- p.1-2
Chapter 1.2. --- Fabrication of metal matrix composites (MMCs) --- p.1-2
Chapter 1.2.1. --- Traditional methods --- p.1-2
Chapter 1.2.1.1. --- Liquid state methods --- p.1-2
Chapter 1.2.1.2. --- Solid state methods --- p.1-4
Chapter 1.2.2. --- In-situ methods --- p.1-5
Chapter 1.3. --- Aluminum based metal matrix composites --- p.1-7
Chapter 1.4. --- Previous works --- p.1-8
Chapter 1.5. --- Works in this study --- p.1-9
Chapter 1.6. --- Thesis layout --- p.1-10
References
Chapter Chapter 2 --- Methodology and instrumentation --- p.2-1
Chapter 2.1. --- Powder metallurgy --- p.2-1
Chapter 2.2. --- Fabrication procedures --- p.2-1
Chapter 2.3. --- Samples to be studied --- p.2-3
Chapter 2.4. --- Instrumentation --- p.2-4
Chapter 2.4.1. --- Differential thermal analyzer (DTA) --- p.2-4
Chapter 2.4.2. --- Argon tube furnace sintering --- p.2-4
Chapter 2.4.3. --- X-ray powder diffractometry (XRD) --- p.2-5
Chapter 2.4.4. --- Scanning electron microscopy (SEM) --- p.2-5
Chapter 2.4.5. --- Three-point bending test --- p.2-5
Chapter 2.4.6. --- Arc melting furnace --- p.2-6
References
Chapter Chapter 3 --- Thermal analysis of Al-Ti02 and Al-Ti02-B203 --- p.3-1
Chapter 3.1. --- Introduction --- p.3-1
Chapter 3.2. --- Results and discussions --- p.3-2
Chapter 3.2.1. --- DTA curve of Al-8.6wt%Ti --- p.3-3
Chapter 3.2.2. --- DTA curve of Al-12.7wt%Ti02 --- p.3-3
Chapter 3.2.3. --- DTA curve of Al-12.7wt%Ti02-5.5wt%B203 --- p.3-5
Chapter 3.2.4. --- DTA curve of Al-12.7wt%Ti02-l lwt%B203 --- p.3-6
Chapter 3.2.5. --- DTA curve of Al-53.6wt%Ti02 --- p.3-7
Chapter 3.2.6. --- "DTA curves of Al-12.7wt%Ti02, 22.3wt%Ti02 and 29.7wt%Ti02" --- p.3-7
Chapter 3.3. --- Conclusions --- p.3-8
References
Chapter Chapter 4 --- Fabrication and characterization of the Al-Ti02 systems --- p.4-1
Chapter 4.1. --- Introduction --- p.4-1
Chapter 4.2. --- Al-12.7wt%Ti02 system --- p.4-2
Chapter 4.2.1. --- Experiments --- p.4-2
Chapter 4.2.2. --- Results and discussions --- p.4-3
Chapter 4.2.2.1. --- XRD spectra --- p.4-3
Chapter 4.2.2.2. --- Microstructural and composition analyses --- p.4-4
Chapter 4.2.3. --- Reaction mechanisms --- p.4-6
Chapter 4.2.4. --- Conclusions --- p.4-8
Chapter 4.3. --- Al-53.6wt%Ti02 system --- p.4-9
Chapter 4.3.1. --- Experiments --- p.4-9
Chapter 4.3.2. --- Sample sintered in tube furnace --- p.4-9
Chapter 4.3.2.1. --- XRD spectra --- p.4-9
Chapter 4.3.2.2. --- Microstructural and EDS analyses --- p.4-10
Chapter 4.3.3. --- Sample prepared by arc-melting method --- p.4-11
Chapter 4.3.3.1. --- XRD spectra --- p.4-11
Chapter 4.3.3.2. --- Microstructural and EDS analyses --- p.4-11
Chapter 4.3.3.3. --- Mechanisms of formation --- p.4-12
Chapter 4.3.4. --- Conclusions --- p.4-14
References
Chapter Chapter 5 --- Characterization of the Al-Ti02-B203 systems --- p.5-1
Chapter 5.1. --- Introduction --- p.5-1
Chapter 5.2. --- Experiments --- p.5-2
Chapter 5.3. --- Results and discussions --- p.5-3
Chapter 5.3.1. --- XRD spectra --- p.5-3
Chapter 5.3.2. --- Microstructural and composition analyses --- p.5-5
Chapter 5.3.3. --- Reaction mechanisms --- p.5-6
Chapter 5.3.4. --- Sample with different contents of B203 --- p.5-7
Chapter 5.4. --- Conclusions --- p.5-8
References
Chapter Chapter 6 --- Flexural strengths of the Al-Ti02 and Al-Ti02-B203 systems --- p.6-1
Chapter 6.1. --- Introduction --- p.6-1
Chapter 6.2. --- Three-point bending test --- p.6-1
Chapter 6.2.1. --- Experiments --- p.6-1
Chapter 6.2.2. --- Results --- p.6-2
Chapter 6.2.3. --- Discussions --- p.6-3
Chapter 6.3. --- Conclusions --- p.6-5
References
Chapter Chapter 7 --- Conclusions and future works --- p.7-1
Chapter 7.1. --- Conclusions --- p.7-1
Chapter 7.2. --- Future works --- p.7-2

by Wai-Yuen Kwok = 氧化鋁及鋁-鉻金屬間化合物增強的鋁基複合材料的製造和表徵 / 郭瑋源.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Wai-Yuen Kwok = Yang hua lü ji lü--ge jin shu jian hua he wu zeng qiang de lü ji fu he cai liao de zhi zao he biao zheng / Guo Weiyuan.
Acknowledgements --- p.i
Abstract --- p.ii
摘要 --- p.iv
List of tables --- p.vi
List of figures --- p.vii
Table of contents --- p.xiv
Chapter Chapter 1 --- Metal matrix composites --- p.1-1
Chapter 1.1 --- Introduction --- p.1-1
Chapter 1.1.2 --- Conventional fabrication processes --- p.1-2
Chapter 1.1.2.1 --- Solid state processes --- p.1-2
Chapter 1.1.2.1.1 --- Powder blending and consolidation --- p.1-2
Chapter 1.1.2.1.2 --- Diffusion bonding --- p.1-3
Chapter 1.1.2.2 --- Liquid state processes --- p.1-3
Chapter 1.1.2.2.1 --- Casting or liquid infiltration --- p.1-3
Chapter 1.1.2.2.2 --- Squeeze infiltration --- p.1-4
Chapter 1.1.2.2.3 --- Stir casting --- p.1-4
Chapter 1.1.2.2.4 --- Spray deposition --- p.1-5
Chapter 1.1.2.3 --- In-situ processes --- p.1-5
Chapter 1.1.3 --- Applications of metal matrix composites --- p.1-6
Chapter 1.1.3.1 --- Aerospace applications --- p.1-6
Chapter 1.1.3.2 --- Non-aerospace applications --- p.1-6
Chapter 1.1.3.3 --- Filamentary superconductors --- p.1-7
Chapter 1.2 --- Reinforcements in metal matrix composites --- p.1-7
Chapter 1.2.1 --- Particles reinforcements --- p.1-8
Chapter 1.2.1.1 --- Definition of intermetallics --- p.1-8
Chapter 1.2.1.2 --- Applications of intermetallics --- p.1-9
Chapter 1.2.2 --- Fiber reinforcements --- p.1-9
Chapter 1.2.2.1 --- Definition of whisker --- p.1-9
Chapter 1.2.2.2 --- Applications of whiskers --- p.1-10
Chapter 1.3 --- Chromium Aluminide --- p.1-10
Chapter 1.3.1 --- Aluminum and Aluminum (III) oxide --- p.1-11
Chapter 1.3.2 --- Chromium and Chromium (III) oxide --- p.1-12
Chapter 1.4 --- Previous work --- p.1-13
Chapter 1.5 --- Current work --- p.1-14
Chapter 1.6 --- Thesis layout --- p.1-15
References
Chapter Chapter 2 --- Methodology and Instrumentation --- p.2-1
Chapter 2.1 --- Introduction --- p.2-1
Chapter 2.2 --- Powder metallurgy --- p.2-1
Chapter 2.2.1 --- "Particle size, pressing pressure, sintering conditions" --- p.2-1
Chapter 2.2.2 --- Sintering process --- p.2-2
Chapter 2.3 --- Fabrication methods --- p.2-4
Chapter 2.3.1 --- Sample preparation --- p.2-4
Chapter 2.3.1.1 --- Al+Cr2〇3 composite samples --- p.2-4
Chapter 2.3.2 --- Cold pressing --- p.2-4
Chapter 2.3.3 --- Box furnace sintering (Sintering in air) --- p.2-5
Chapter 2.3.4 --- Argon tube furnace sintering (Sintering in argon) --- p.2-5
Chapter 2.3.5 --- Hot-press sintering --- p.2-6
Chapter 2.3.6 --- Arc melting --- p.2-7
Chapter 2.4 --- Characterization methods --- p.2-8
Chapter 2.4.1 --- Thermal analysis - Differential thermal analyzer (DTA) --- p.2-8
Chapter 2.4.2 --- Physical property analysis - Relative density measurement --- p.2-9
Chapter 2.4.3 --- Mechanical property - Vickers hardness measurement --- p.2-10
Chapter 2.4.4 --- Microstructural analysis - Scanning electron microscopy (SEM) --- p.2-10
Chapter 2.4.5 --- Phases determination - X-ray powder diffractometry (XRD) --- p.2-11
References
Chapter Chapter 3 --- Thermal analysis of Al-Cr203 powder mixture --- p.3-1
Chapter 3.1 --- Introduction --- p.3-1
Chapter 3.2 --- Experimental details --- p.3-2
Chapter 3.3 --- Results --- p.3-2
Chapter 3.3.1 --- DTA curves --- p.3-2
Chapter 3.3.2 --- XRD patterns --- p.3-3
Chapter 3.3.3 --- SEM micrographs --- p.3-4
Chapter 3.4 --- Discussions --- p.3-5
Chapter 3.5 --- Formation of Al-Cr203 MMCs --- p.3-8
Chapter 3.6 --- Conclusions --- p.3-8
References
Chapter Chapter 4 --- Fabrication and characterization of the Al-Cr203 MMCs --- p.4-1
Chapter 4.1 --- Introduction --- p.4-1
Chapter 4.2 --- Experimental details --- p.4-1
Chapter 4.3 --- Results --- p.4-2
Chapter 4.3.1 --- Al-MMCs produced by different sintering methods --- p.4-2
Chapter 4.3.1.1 --- XRD patterns --- p.4-2
Chapter 4.3.1.2 --- SEM micrographs --- p.4-4
Chapter 4.3.2 --- Argon-sintered Al-MMCs with different sintering time --- p.4-6
Chapter 4.3.2.1 --- XRD patterns --- p.4-6
Chapter 4.3.2.2 --- SEM micrographs --- p.4-7
Chapter 4.4 --- Discussions --- p.4-8
Chapter 4.5 --- Mechanism in the formation of Al-Cr203 MMCs --- p.4-9
Chapter 4.6 --- Conclusions --- p.4-10
References
Chapter Chapter 5 --- Physical and mechanical properties of Al-Cr203 system --- p.5-1
Chapter 5.1 --- Introduction --- p.5-1
Chapter 5.2 --- Experimental details --- p.5-1
Chapter 5.3 --- Relativity density --- p.5-2
Chapter 5.3.1 --- Measurement --- p.5-2
Chapter 5.3.2 --- Discussions --- p.5-4
Chapter 5.4 --- Mechanical hardness --- p.5-5
Chapter 5.4.1 --- Measurement --- p.5-5
Chapter 5.4.2 --- Discussions --- p.5-6
Chapter 5.5 --- Conclusions --- p.5-7
References
Chapter Chapter 6 --- Fabrication and characterization of Al-Cr203 MMCs fabricated by arc melting --- p.6-1
Chapter 6.1 --- Introduction --- p.6-1
Chapter 6.2 --- Experimental Details --- p.6-1
Chapter 6.3 --- Results --- p.6-2
Chapter 6.3.1 --- Unannealed arc-melted samples --- p.6-2
Chapter 6.3.1.1 --- XRD patterns --- p.6-2
Chapter 6.3.1.2 --- SEM micrographs --- p.6-2
Chapter 6.3.2 --- Annealed arc-melted samples --- p.6-4
Chapter 6.3.2.1 --- XRD patterns --- p.6-4
Chapter 6.3.2.2 --- SEM micrographs --- p.6-4
Chapter 6.4 --- Discussions --- p.6-5
Chapter 6.5 --- Formation of Al-MMCs during the arc-melting method --- p.6-6
Chapter 6.6 --- Vickers hardness --- p.6-7
Chapter 6.7 --- Conclusions --- p.6-8
References
Chapter Chapter 7 --- Conclusions and future works --- p.7-1
Chapter 7.1 --- Conclusions --- p.7-1
Chapter 7.2 --- Future works --- p.7-2

by Ho Man Wai.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Ho Man Wai.
Abstract --- p.i
Acknowledgement --- p.v
Table of Contents --- p.vi
List of Tables --- p.xi
List of Figures --- p.xii
Chapter Chapter 1 --- Intermetallics
Chapter 1.1 --- Background --- p.1-1
Chapter 1.2 --- Applications of intermetallics --- p.1-4
Chapter 1.2.1 --- Structural materials --- p.1-4
Chapter 1.2.2 --- Magnetic materials --- p.1-6
Chapter 1.2.3 --- Superconducting materials --- p.1-6
Chapter 1.2.4 --- Hydrogen storage materials --- p.1-7
Chapter 1.2.5 --- Shape memory alloys --- p.1-7
Chapter 1.2.6 --- Heating elements --- p.1-8
Chapter 1.3 --- Prospects of intermetallics --- p.1-8
References --- p.1-10
Tables --- p.1-12
Figures --- p.1-13
Chapter Chapter 2 --- Metal matrix composites
Chapter 2.1 --- Metal matrix composites --- p.2-1
Chapter 2.2 --- Conventional fabrication processes of MMCs --- p.2-2
Chapter 2.2.1 --- Liquid state processes --- p.2-3
Chapter 2.2.1.1 --- Casting or liquid infiltration --- p.2-3
Chapter 2.2.1.2 --- Squeeze casting or pressure infiltration --- p.2-3
Chapter 2.2.2 --- Solid state processes --- p.2-3
Chapter 2.2.2.1 --- Diffusion bonding --- p.2-3
Chapter 2.2.2.2 --- Deformation processing --- p.2-4
Chapter 2.2.2.3 --- Powder processing --- p.2-5
Chapter 2.2.3 --- In situ process --- p.2-6
Chapter 2.3 --- Applications of metal matrix composites --- p.2-7
Chapter 2.3.1 --- Aerospace applications --- p.2-7
Chapter 2.3.2 --- Non-aerospace applications --- p.2-7
Chapter 2.3.3 --- Filamentary superconductors --- p.2-7
References --- p.2-9
Chapter Chapter 3 --- Molybdenum Aluminide
Chapter 3.1 --- Introduction --- p.3-1
Chapter 3.2 --- Aluminum --- p.3-1
Chapter 3.3 --- Molybdenum --- p.3_2
Chapter 3.4 --- Previous research work --- p.3.3
Chapter 3.5 --- Present research work --- p.3-4
Chapter 3.6 --- Thesis layout --- p.3-6
References --- p.3-8
Figures --- p.3-9
Chapter Chapter 4 --- Methodology and Instrumentation
Chapter 4.1 --- Introduction --- p.4-1
Chapter 4.2 --- Powder metallurgy --- p.4-1
Chapter 4.3 --- Fabrication methods --- p.4-4
Chapter 4.3.1 --- Sample preparation --- p.4-4
Chapter 4.3.1.1 --- Intermetallic samples --- p.4-4
Chapter 4.3.1.2 --- A1 + Al-Mo composite samples --- p.4-5
Chapter 4.3.2 --- Cold pressing --- p.4-5
Chapter 4.3.3 --- Sintering --- p.4-5
Chapter 4.3.4 --- Arc melting --- p.4-6
Chapter 4.3.5 --- Hot pressing --- p.4-7
Chapter 4.4 --- Characterization methods --- p.4-8
Chapter 4.4.1 --- Thermal analysis --- p.4-8
Chapter 4.4.1.1 --- Differential Thermal Analyzer (DTA) --- p.4-8
Chapter 4.4.2 --- Mechanical analysis --- p.4-9
Chapter 4.4.2.1 --- Tensile Tests --- p.4.9
Chapter 4.4.2.2 --- Vickers´ةHardness Tests --- p.4-10
Chapter 4.4.2.3 --- Relative density measurement --- p.4-10
Chapter 4.4.3 --- Structural analysis --- p.4-12
Chapter 4.4.3.1 --- Scanning Electron Microscopy (SEM) --- p.4-12
Chapter 4.4.3.2 --- X-Ray powder Diffractometry (XRD) --- p.4-12
References --- p.4-13
Figures --- p.4-14
Chapter Chapter 5 --- Thermal analysis on the reaction mechanism of the Al-Mo system
Chapter 5.1 --- Introduction --- p.5-1
Chapter 5.2 --- Experimental details --- p.5-2
Chapter 5.3 --- Results and discussions --- p.5-2
Chapter 5.3.1 --- "DTA, XRD and SEM analyses of A1 - 57wt% Mo" --- p.5-2
Chapter (A) --- Temperature < 630°C --- p.5-3
Chapter (B) --- 630°。C < Temperature < 660°C --- p.5-3
Chapter (C) --- 660°C < Temperature < 670°。C --- p.5-4
Chapter (D) --- 670°C < Temperature < 730°C --- p.5-5
Chapter (E) --- Temperature up to 900°C --- p.5-5
Chapter (F) --- A brief conclusion --- p.5-6
Chapter 5.3.2 --- "DTA, XRD and SEM analyses of A1 - 91wt% Mo" --- p.5-6
Chapter (A) --- Temperature < 630°C --- p.5.7
Chapter (B) --- 630°。C < Temperature < 660°。C --- p.5-7
Chapter (C) --- Temperature up to 900°C --- p.5-8
Chapter 5.4 --- Summary --- p.5-8
References --- p.5-10
Tables --- p.5-11
Figures --- p.5-12
Chapter Chapter 6 --- Fabrication and characterization of the intermetallic Mo3A18
Chapter 6.1 --- Introduction --- p.6-1
Chapter 6.2 --- Experimental details --- p.6-1
Chapter 6.3 --- Results and discussions --- p.6-2
Chapter 6.3.1 --- X-ray powder diffraction analysis --- p.6-2
Chapter 6.3.2 --- Microstructure analysis --- p.6-4
Chapter 6.3.3 --- "Vickers, hardness measurement" --- p.6-5
Chapter 6.3.4 --- Relative density measurement --- p.6-7
Chapter 6.4 --- Summary --- p.6-7
Figures --- p.6-9
Chapter Chapter 7 --- Thermal analysis on the formation of the AI-Mo3A18 composites
Chapter 7.1 --- Introduction --- p.7-1
Chapter 7.2 --- Experimental details --- p.7-2
Chapter 7.3 --- Results and discussions --- p.7-2
Chapter 7.3.1 --- DTA and XRD analyses of samples heated up to 700°C --- p.7-3
Chapter 7.3.2 --- DTA and XRD analyses of samples heated up to 900°C --- p.7-4
Chapter 7.4 --- Summary --- p.7-6
Reference --- p.7-7
Tables --- p.7-8
Figures --- p.7-9
Chapter Chapter 8 --- Fabrication and characterization of the A1-Mo3A18 metal matrix composites
Chapter 8.1 --- Introduction --- p.8-1
Chapter 8.2 --- Experimental details --- p.8-1
Chapter 8.3 --- Results and discussions --- p.8-2
Chapter 8.3.1 --- Tensile tests --- p.8-2
Chapter 8.3.2 --- X-ray powder diffraction analysis --- p.8-5
Chapter 8.3.3 --- Microstructure analysis --- p.8-6
Chapter 8.3.4 --- Vickers' hardness measurement --- p.8-7
Chapter 8.3.5 --- Relative density measurement --- p.8-8
Chapter 8.4 --- Summary --- p.8-9
References --- p.8-11
Figures --- p.8-12
Chapter Chapter 9 --- Conclusions and future studies
Chapter 9.1 --- Conclusions --- p.9-1
Chapter 9.2 --- Future studies --- p.9-3

by Peng Yu.
"Oct. 2003."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.
by Peng Yu.

by Che-Kit Lo.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Che-Kit Lo.
Acknowledgements --- p.i
Abstract --- p.ii
摘要 --- p.iv
List of Tables --- p.v
List of Figures --- p.vi
Table of contents --- p.xi
Chapter Chapter 1 --- Metal matrix composites --- p.1-1
Chapter 1.1 --- Introduction --- p.1-1
Chapter 1.1.2 --- Conventional fabrication processes --- p.1-2
Chapter 1.1.2.1 --- Solid phase processes --- p.1-2
Chapter 1.1.2.1.1 --- Powder blending and consolidation --- p.1-2
Chapter 1.1.2.1.2 --- Diffusion bonding --- p.1-3
Chapter 1.1.2.2 --- Liquid phase processes --- p.1-3
Chapter 1.1.2.2.1 --- Casting or liquid infiltration --- p.1-3
Chapter 1.1.2.2.2 --- Squeeze infiltration --- p.1-3
Chapter 1.1.2.2.3 --- Stir casting --- p.1-4
Chapter 1.1.2.2.4 --- Spray deposition --- p.1-4
Chapter 1.1.2.3 --- In-situ processes --- p.1-5
Chapter 1.1.3 --- Applications of metal matrix composites --- p.1-5
Chapter 1.1.3.1 --- Aerospace applications --- p.1-5
Chapter 1.1.3.2 --- Non-aerospace applications --- p.1-6
Chapter 1.1.3.3 --- Filamentary superconductors --- p.1-6
Chapter 1.2 --- Reinforcements --- p.1-7
Chapter 1.2.1 --- Particles reinforcements --- p.1-7
Chapter 1.2.1.1 --- Definition of intemetallics --- p.1-7
Chapter 1.2.1.2 --- Application of intemetallics --- p.1-8
Chapter 1.2.2 --- Fiber reinforcements --- p.1-8
Chapter 1.2.2.1 --- Definition of whisker --- p.1-8
Chapter 1.2.2.2 --- Application of whisker --- p.1-9
Chapter 1.3 --- Tungsten Aluminide --- p.1-9
Chapter 1.3.1 --- Aluminum and its oxide --- p.1-10
Chapter 1.3.2 --- Tungsten and its oxide --- p.1-11
Chapter 1.4 --- Previous research work --- p.1-12
Chapter 1.5 --- Recent research work --- p.1-13
Chapter 1.6 --- Thesis layout --- p.1-14
References
Chapter Chapter 2 --- Methodology and Instrumentation --- p.2-1
Chapter 2.1 --- Introduction --- p.2-1
Chapter 2.2 --- Powder metallurgy --- p.2-1
Chapter 2.3 --- Fabrication methods --- p.2-3
Chapter 2.3.1 --- Cold pressing --- p.2-3
Chapter 2.3.2 --- Standard Sintering --- p.2-4
Chapter 2.3.3 --- Argon tube furnace sintering --- p.2-5
Chapter 2.3.4 --- Hot pressing --- p.2-5
Chapter 2.4 --- Characterization methods --- p.2-6
Chapter 2.4.1 --- Thermal analysis --- p.2-6
Chapter 2.4.1.1 --- Differential Thermal Analyzer (DTA) --- p.2-6
Chapter 2.4.2 --- Mechanical analysis --- p.2-7
Chapter 2.4.2.1 --- Relative density measurement --- p.2-7
Chapter 2.4.2.2 --- Tensile Tests --- p.2-8
Chapter 2.4.2.3 --- Vickers Hardness Tests --- p.2-8
Chapter 2.4.3 --- Structural analysis --- p.2-10
Chapter 2.4.3.1 --- Scanning Electron Microscopy (SEM) --- p.2-10
Chapter 2.4.3.2 --- X-Ray powder diffractometry (XRD) --- p.2-10
References
Chapter Chapter 3 --- Thermal analysis on the reaction mechanism of the A1-W03 system --- p.3-1
Chapter 3.1 --- Introduction --- p.3-1
Chapter 3.2 --- Experimental details --- p.3-1
Chapter 3.3 --- Results and discussions --- p.3-2
Chapter 3.3.1 --- Analysis of the Al-58wt%W intermetallics --- p.3-2
Chapter 3.3.2 --- Analysis of the Al-36wt%W intermetallics --- p.3-5
Chapter 3.3.3 --- Analysis of the Al-30wt%WO3 intermetallics --- p.3-6
Chapter 3.4 --- Conclusions --- p.3-8
References
Chapter Chapter 4 --- Fabrication and characterization of A1-WO3 MMCs --- p.4-1
Chapter 4.1 --- Introduction --- p.4-1
Chapter 4.2 --- Experiments details --- p.4-1
Chapter 4.3 --- Results and discussion --- p.4-2
Chapter 4.3.1 --- X-Ray powder diffraction analysis --- p.4-2
Chapter 4.3.2 --- Microstructure analysis (SEM) --- p.4-3
Chapter 4.3.2.1 --- SEM micrographs of Hot pressed samples --- p.4-3
Chapter 4.3.2.2 --- SEM micrographs of samples sintered in argon tube furnace --- p.4-4
Chapter 4.4 --- Formation of A1-WO3 MMCs --- p.4-5
Chapter 4.5 --- Conclusions --- p.4-5
References
Chapter Chapter 5 --- Physical and mechanic properties of the A1-W03 MMCs
Chapter 5.1 --- Introduction --- p.5-1
Chapter 5.2 --- Experiments details --- p.5-1
Chapter 5.3 --- X-ray powder diffraction analysis --- p.5-1
Chapter 5.4 --- Mechanic properties --- p.5-2
Chapter 5.4.1 --- Relative density --- p.5-2
Chapter 5.4.2 --- Vickers hardness measurement --- p.5-3
Chapter 5.4.3 --- Tensile Strength measurement --- p.5-4
Chapter 5.5 --- Conclusions --- p.5-5
References
Chapter Chapter 6 --- Conclusions and future works --- p.6-1
Chapter 6.1 --- Conclusions --- p.6-1
Chapter 6.2 --- Future Works --- p.6-2

The subject of this work subscribes to the international preoccupation regarding the elucidation of magnetic properties of solids. The crystallographic, electronic and magnetic structures of Al-Mn-Ni alloys and compounds have been investigated by X-ray diffraction, magnetization and magnetic susceptibility measurements, X-ray photoelectron spectroscopy (XPS), and band structure calculations. The thesis is organized in 6 Chapters, followed by the summary. Chapter 1 contains a brief theoretical introduction into the magnetism of metallic systems, as well the principles of XPS. The sample preparation details and all the techniques employed in the characterization of the systems are described in Chapter 2. The next 4 Chapters contain the experimental results for Mn1-xAlxNi3, Mn1-xAlxNi, Ni1-xMnxAl, Ni0.7-xAlxMn0.3 systems.