Equal channel angular pressing of elemental & alloyed P/M aluminium systems

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Harrison, Nicholas (2014). Equal channel angular pressing of elemental & alloyed P/M aluminium systems. University of Birmingham. Ph.D.

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Abstract

Aluminium powder metallurgy provides lightweight automobile components for reduced energy consumption. Conventional press-and-sinter methods can leave porosity in final parts, which reduces strength of the alloy. Equal Channel Angular Pressing (ECAP) can be used to increase density of powder compacts after sintering via severe plastic deformation.

Solid state sintering of pure aluminium and liquid phase sintering of a commercial Al-Sn bearing alloy were analysed with industrial collaborative support. The use of room temperature ECAP to these sintered materials was investigated.

Cold compaction produced a porous region on the outside of all samples due to increased friction at the die wall. The application of ECAP to pure aluminium and bearing alloys caused elongation in the longitudinal section and a relatively equiaxed microstructure in the transverse section.

Sintering at 500°C for 1 and lOhours and 550°C for lh was ineffective as liquid tin did not wet the aluminium effectively. After ECAP, density and hardness increased with refined grain sizes and formed two distinct regions; a denser, deformed core and a non-deformed skin, which resulted from non-uniform densification after cold compaction.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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