The thesis paper here focuses on the effects of the austempering temperature (TA) and the austempering time (tA) on the unalloyed fully ferrite Compacted Graphite Iron (CGI), to obtain improve in mechanical properties and the study of the microstructure. The unalloyed CGI samples were austenitised at 850oC for 60 and 90 min and were then heat treated at 275, 325 and 375oC with different holding times at 30,60,90, and 120 mins. Mechanical properties like the tensile strength, yield strength, young’s modulus, Brinell and Vickers harness were conducted to perform the analysis on the samples. LOM was used for the study of the microstructure and SEM was used for the study of fractography of the fractured tensile bar.

Superalloys such as alloy 718 and 925 possesses superior properties at elevated temperatures and corrosive environments. They are commonly found in application such as oil and gas extraction, turbine engines and in the chemistry industry. These alloys were developed during the 1950s but the demand of tubes and pipes of these alloys has rapidly increased. Sandvik has recently started produce these products and faces new challenges within the production.There are several studies within the area of superalloys but the hot working behavior and flow softening mechanism are not fully understood.The goal with this master thesis is to analyze two different steel grades, alloy 718 and 925 and correlate different process parameters that will influence the recrystallization initiation and nucleation.Two ingots manufactured through electric arc furnace, argon oxygen decarburization and refined by vacuum arc remelting were analyzed followed by a homogenization heat treatment. Samples were extracted from three positions, bottom, center, top and from half the radius in the ingot. The chemical composition was analyzed and the mechanical properties was tested trough hot compression testing (Gleeble). From Gleeble testing, the true strain, stress curves were analyzed in order to determine flow softening effects. The microstructure were studied trough light optical microscopy and electron backscatter diffraction.The results reveal that discontinuous dynamic recystallization is the dominant flow softening mechanism. There was no significant difference between the three positioning within the ingot.To maximize the recrystallized area fraction higher strain and temperatures must be provided or lower strain rates.

A Dissertation submitted to the Faculty of Science, School of Chemistry, University of Witwatersrand in fulfillment of the requirements for the degree of Master of Science. Johannesburg 2014 / The resin-gel method of synthesis successfully produced compounds of mixed metal oxides of copper titanium oxide powders of the form CuxTiyOZ with different compositions. These include Cu3TiO5, Cu3TiO4, Ti3Cu3O, Cu2Ti4O, Cu2Ti2O5 and Cu2TiO3. Heat-treatment of the powders at 300°C, 500°C, 700°C and 900°C for 1 hour was performed to determine the full composition/temperature phase diagram. The target particle size was in the 10- nanometer range, and for most of the samples, this size was achieved. Powder xray diffraction and transmission electron microscopy were the main techniques used to study the crystallization of these materials and their transformation to other polymorphic phases under different temperatures. Phase-match, particle size analysis and TEM imaging determined the properties and characteristics of the respective crystallographic phases of these materials. TEM analysis showed that some powders agglomerated while others exhibited both regular and irregular morphologies and polydisperse particle size distribution. Only a single unique phase was identified, but its structure could not be determined.

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This Independent Project reviews literature about the effect of pressure and temperature on thermal conductivity in packed beds and its relationship with electrical conductivity. Exploring the relationships between thermal conductivity, porosity and pressure can give useful knowledge for further improvements in manufacturing processes in the field of powder metallurgy. The resulting theoretical models describing the effective thermal conductivity show that gas and contact conductance dominate at lower temperatures and that radiation gains dominance as the temperature increases. Modifications of the models covered in this report can be made in order to simulate the process of interest more accurately. It was also shown that Wiedemann-Franz law could be of interest when wanting to quantify the thermal conductivity in a powder compact. Furthermore, a lab manual for a future Independent Project was developed.

Neste trabalho foram estudadas 10 corridas em duas usinas siderúrgicas semi-integradas, de aço baixa liga para uso em construção mecânica. Em cada uma das corridas foram retiradas 9 amostras, cada uma ao final de uma etapa do processo de produção: após a remoção de escória na panela, antes da desgaseificação a vácuo, após a desgaseificação a vácuo, após a adição de arame de Al, após a adição de arame de CaSi, após a adição de arame de S, após o fim da turbulência no distribuidor no lingotamento contínuo, 30 minutos após o fim da turbulência no distribuidor no lingotamento contínuo, e 60 minutos após o fim da turbulência no distribuidor no lingotamento contínuo. As amostras foram preparadas metalograficamente e analisadas ao microscópio eletrônico de varredura (MEV) com espectrometria de dispersão de energia (EDS), a fim de se identificar as inclusões presentes no aço em cada etapa do processo. Com isto pode-se fazer a caracterização das inclusões encontradas em cada etapa do processo e a sua classificação segundo a composição química e morfologia. Através da comparação da composição química das inclusões encontradas ao final do refino e no lingotamento contínuo foi possível verificar uma tendência de formação de inclusões de espinélio, e através da composição química das inclusões encontradas no lingotamento contínuo foi possível identificar em quais das corridas estudadas houve a presença de inclusões de aluminatos de cálcio formados no estado líquido. / In the present work it was studied 10 heats in two steelworks, of low alloyed steel for use in mechanical construction. From each heat were taken 9 samples, each one of them at end of one production stage: after deslagging in the ladle; before vacuum degassing; after vacuum degassing; after Al wire addiction; after CaSi wire addiction; after S wire addiction; after the end of tundish turbulence at continuously casting; 30 minutes after the end of tundish turbulence at continuously casting; and 60 minutes after the end of tundish turbulence at continuously casting. Samples were metallographic prepared and analyzed by scanning electronic microscopic (SEM) with energy dispersive X-ray spectroscopy (EDX), in order to identify the inclusions present in steel in each process stage. This allowed the founded inclusions in each process stage to be characterized and classified according to chemical composition and morphology. By comparing founded inclusions chemical composition at end of refining and continuous casting was possible to observe a tendency of formation of spinel inclusions, and by founded inclusions chemical composition in continuous casting was possible to identify in which studied heats there were presence calcium aluminates inclusions formed in the liquid state.

by Tong Kwok Wang. / Parallel title in Chinese characters. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 71-74. / Acknowledgement / Abstract / Chapter 1. --- Introduction / Chapter 1.1 --- General Introduction --- p.1 / Chapter 1.2 --- Properties --- p.5 / Chapter 1.3 --- Background of this research --- p.10 / Chapter 1.4 --- The Present Experiment --- p.11 / Chapter 2. --- Theory / Chapter 2.1 --- Conduction Mechanism --- p.15 / Chapter 2.2 --- Temperature Dependence of Thermal Conductivity --- p.16 / Chapter 2.3 --- Phonon Conductivity and phonon mean free path --- p.20 / Chapter 3. --- Experimental / Chapter 3.1 --- Thermal Diffusivity by Laser Photothermal Radiometry --- p.22 / Chapter 3.2 --- Resistivity Measurement --- p.30 / Chapter 3.3 --- Sample Preparation --- p.36 / Chapter 3.4 --- Data Analysis --- p.37 / Chapter 4. --- Results and Discussion / Chapter 4.1 --- Thermal Conductivity --- p.41 / Chapter 4.2 --- Electronic Thermal Conductivity --- p.47 / Chapter 4.3 --- Phonon Thermal Conductivity --- p.52 / Chapter 4.4 --- Phonon Mean Free Path --- p.58 / Chapter 5. --- Conclusion and Suggestions for Further Work --- p.68 / References --- p.71 / Appendixes --- p.75

Ka-fai Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Ka-fai Ho. / Acknowledgments --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Figures Captions --- p.v / Tables Captions --- p.xii / Table of contents --- p.xiii / Chapter Chapter one --- Introduction --- p.1-1 / Chapter 1.1 --- Metal Matrix Composite --- p.1-1 / Chapter 1.1.1 --- Matrix Materials --- p.1-2 / Chapter 1.1.1.1 --- Aluminum --- p.1-2 / Chapter 1.1.1.2 --- Titanium --- p.1-3 / Chapter 1.1.2 --- Type of reinforcements --- p.1-3 / Chapter 1.2 --- Conventional Fabrication method --- p.1-4 / Chapter 1.2.1 --- Liquid Phase processing --- p.1-4 / Chapter 1.2.1.1 --- Slurry deposition --- p.1-4 / Chapter 1.2.1.2 --- Squeeze casing (Pressure infiltration) --- p.1-4 / Chapter 1.2.2 --- Solid Phase processing --- p.1-5 / Chapter 1.2.2.1 --- Diffusion bonding --- p.1-5 / Chapter 1.2.2.2 --- Powder Metallurgy (P/M) --- p.1-5 / Chapter 1.2.3 --- In-situ processing --- p.1-7 / Chapter 1.3 --- Sintering processing --- p.1-7 / Chapter 1.3.1 --- Pore structure --- p.1-8 / Chapter 1.3.2 --- Compression effect on sintering --- p.1-9 / References / Chapter Chapter Two --- Methodology and Instrumentation --- p.2-1 / Chapter 2.1 --- Al-Ti-C composites --- p.2-1 / Chapter 2.1.1 --- Introduction --- p.2-1 / Chapter 2.1.2 --- Aim and Motivation --- p.2-2 / Chapter 2.1.2.1 --- Compositions and Fabrications --- p.2-2 / Chapter 2.1.2.2 --- Testing --- p.2-3 / Chapter 2.1.3 --- The Flow of the Thesis --- p.2-3 / Chapter 2.2 --- Instrumentation --- p.2-4 / Chapter 2.2.1 --- Ball-milling machine --- p.2-4 / Chapter 2.2.2 --- High temperature furnace --- p.2-5 / Chapter 2.2.3 --- Arc-melting furnace --- p.2-5 / Chapter 2.2.4 --- Instron loading machine --- p.2-6 / Chapter 2.2.5 --- Density measurement --- p.2-6 / Chapter 2.2.6 --- Vickers' Hardness Tester --- p.2-8 / Chapter 2.2.7 --- X-ray diffraction analysis --- p.2-8 / Chapter 2.2.8 --- Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDXS) --- p.2-9 / References / Chapter Chapter Three --- Fabrication of Al-16Ti-C composites by Powder Metallurgy method --- p.3-1 / Chapter 3.1 --- Introduction --- p.3-1 / Chapter 3.2 --- Experiments --- p.3-1 / Chapter 3.2.1 --- Experiments on Pressing pressure --- p.3-1 / Chapter 3.2.2 --- Firing temperature and duration time --- p.3-2 / Chapter 3.3 --- Results --- p.3-2 / Chapter 3.3.1 --- Pressing pressure --- p.3-2 / Chapter 3.3.1.1 --- Relative Density --- p.3-2 / Chapter 3.3.1.2 --- Surface Porosity --- p.3-2 / Chapter 3.3.1.3 --- Microhardness --- p.3-3 / Chapter 3.3.1.4 --- X-ray diffraction analysis --- p.3-3 / Chapter 3.3.1.5 --- Microstructure --- p.3-3 / Chapter 3.3.2 --- Firing temperature and duration time --- p.3-4 / Chapter 3.3.2.1 --- Microhardness --- p.3-4 / Chapter 3.3.2.2 --- X-ray diffraction analysis --- p.3-4 / Chapter 3.3.2.3 --- Microstructure --- p.3-4 / Chapter 3.4 --- Discussion --- p.3-5 / Chapter 3.4.1 --- Pressing pressure --- p.3.5 / Chapter 3.4.2 --- Firing temperature and time duration --- p.3-6 / Chapter 3.5 --- Conclusions --- p.3-6 / References / Chapter Chapter Four --- Effects of the size of Aluminum powder on the properties of Al-16Ti-4C composites --- p.4-1 / Chapter 4.1 --- Introduction --- p.4-1 / Chapter 4.2 --- Experiments --- p.4-1 / Chapter 4.3 --- Results --- p.4-2 / Chapter 4.3.1 --- Relative density --- p.4-2 / Chapter 4.3.2 --- Microhardness --- p.4-3 / Chapter 4.3.3 --- Fracture Strength --- p.4-3 / Chapter 4.3.4 --- X-ray diffraction analysis --- p.4-3 / Chapter 4.3.5 --- Microstructure --- p.4-4 / Chapter 4.3.5.1 --- Microstructure of the surface --- p.4-4 / Chapter 4.3.5.2 --- Microstructure of the fracture surface --- p.4-4 / Chapter 4.4 --- Discussion --- p.4-5 / Chapter 4.4.1 --- Sintering procedure --- p.4-5 / Chapter 4.4.2 --- Fracture model --- p.4-6 / Chapter 4.4.3 --- X-ray diffraction analysis --- p.4-6 / Chapter 4.5 --- Conclusions --- p.4-7 / References / Chapter Chapter Five --- Effects of different sintering temperature on the properties of Al-16Ti-4C composites --- p.5-1 / Chapter 5.1 --- Introduction --- p.5-1 / Chapter 5.2 --- Experiments --- p.5-1 / Chapter 5.3 --- Results --- p.5-2 / Chapter 5.3.1 --- Relative density --- p.5-2 / Chapter 5.3.2 --- Microhardness --- p.5-2 / Chapter 5.3.3 --- Fracture Strength --- p.5-2 / Chapter 5.3.4 --- X-ray diffraction analysis --- p.5-2 / Chapter 5.3.5 --- Microstructure --- p.5-3 / Chapter 5.3.5.1 --- Surface microstructure --- p.5-3 / Chapter 5.3.5.2 --- Fracture surface microstructure --- p.5-3 / Chapter 5.4 --- Discussion --- p.5-3 / Chapter 5.4.1 --- Sintering procedure and microstructure --- p.5-3 / Chapter 5.4.2 --- Hardness and fracture strength --- p.5-4 / Chapter 5.4.3 --- Model of fracture --- p.5-5 / Chapter 5.5 --- Conclusions --- p.5-5 / Chapter Chapter Six --- Fabrication of TiC by Arc melting method --- p.6-1 / Chapter 6.1 --- Introduction --- p.6-1 / Chapter 6.2 --- Experiments --- p.6-2 / Chapter 6.3 --- Results --- p.6-2 / Chapter 6.3.1 --- X-ray diffraction analysis --- p.6-2 / Chapter 6.3.2 --- Microstructure --- p.6-2 / Chapter 6.4 --- Discussion --- p.6-2 / Chapter 6.4.1 --- Composition --- p.6-2 / Chapter 6.4.2 --- Sintering process --- p.6-3 / Chapter 6.5 --- Conclusions --- p.6-3 / References / Chapter Chapter Seven --- The Effects of the contents of Ti and C on the properties of Al-TiC and Al-Ti-C composites --- p.7-1 / Chapter 7.1 --- Introduction --- p.7-1 / Chapter 7.2 --- Experiments --- p.7-1 / Chapter 7.3 --- Results --- p.7-2 / Chapter 7.3.1 --- Relative density --- p.7-2 / Chapter 7.3.2 --- Microhardness --- p.7-2 / Chapter 7.3.3 --- Fracture Strength --- p.7-2 / Chapter 7.3.4 --- X-ray diffraction analysis --- p.7-3 / Chapter 7.3.5 --- Microstructure --- p.7-3 / Chapter 7.3.5.1 --- Surface microstructure --- p.7-3 / Chapter 7.3.5.2 --- Fracture surface microstructure --- p.7-4 / Chapter 7.4 --- Discussion --- p.7-4 / Chapter 7.4.1 --- Hardening effect --- p.7-4 / Chapter 7.4.2 --- Relationship between fracture strength and relative density --- p.7-4 / Chapter 7.4.3 --- Fracture model --- p.7-5 / Chapter 7.5 --- Conclusions --- p.7-5 / References / Chapter Chapter Eight --- Conclusions and Future Work --- p.8-1 / Chapter 8.1 --- Summary --- p.8-1 / Chapter 8.2 --- Future Work --- p.8-2 / References

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

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