Preparation and characterization of al-al2o3 graded composite materials under different sintering conditions
Functionally graded materials (FGMs) refer to advanced composite materials where the compositions and microstructures are locally varied to allow certain variations of local material properties. In this research, the combination of aluminium (Al) as the metallic phase, and aluminium oxide (Al2O3) as...
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/34302/1/Preparation%20and%20characterization%20of%20al-al2o3.pdf |
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| Summary: | Functionally graded materials (FGMs) refer to advanced composite materials where the compositions and microstructures are locally varied to allow certain variations of local material properties. In this research, the combination of aluminium (Al) as the metallic phase, and aluminium oxide (Al2O3) as ceramic phase in Al -Al2O3graded composite materials are investigated because of mismatch of their thermal properties. The main objective of this research is to investigate the defects and failures such as delamination, decohesion and cracks that might occur during processing which influenced the sintering parameters on density, radial shrinkage, micro-hardness and microstructure of Al-Al2O3 graded structures. This thesis reports the preparation of the four-layered aluminium-aluminium oxide (Al-Al2O3) graded composite materials using powder metallurgy techniques, including the preparation of powders, cold compaction and pressure-less sintering. The free defects four-layered Al-Al2O3 graded composite materials were successfully fabricated under different sintering profile s (two-step and three-step), temperature (600°C and 620°C) and time (120 min and 180 min). The AlAl2O3 FGM have been analysed to find out the effect of sintering conditions on density, shrinkage, micro-hardness and microstructural. From the result of experimental study, densification and micro-hardness of Al-Al2O3FGM improves as the sintering time gives most significant roles during processing. While, shrinkage and microstructure of Al Al2O3 FGM depending upon the sintering temperature. From the microstructural analysis of Al-Al2O3 FGM, it was found that uniform distribution of Al2O3ceramic particles in the Al matrix in all three layers mixed composition with minimum agglomeration. All sintering conditions chosen such as temperature, time and profile, play main role as the micrograph indicated the improvement in distribution, size of pores and interfacial layer with almost straight and parallel line, rather than wavy lines . |
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