Microstructural characterisation and heat treatment refinement of a particulate reinforced aluminium metal matrix composite

Hayes, Ian (2018). Microstructural characterisation and heat treatment refinement of a particulate reinforced aluminium metal matrix composite. University of Birmingham. Ph.D.

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Abstract

The purpose of this work was to determine the microstructure and secondary phase distribution in the TiB2 particulate reinforced Al-4.5Cu A205 alloy. This was extended to sand, investment and die casting techniques with the overall aim of optimising the existing solution heat treatment protocol for a variety of possible starting conditions. Additional work was aimed at determining a relationship between TiB2 additions and the observed globular microstructure. Hardness testing, DSC analysis, EDS and tensile testing were used to determine the effectiveness of heat treatment. It was found that a 4hr solution treatment at 538oC did not produce significantly different results from a 44hr, four step treatment process. As the diffusion behaviour of Cu was judged to be the most important factor affecting solution heat treatment, a simple microstructural model of typical A205 grain structures was proposed. The model was found to operate on similar timescales to those observed from experimental testing of A205 but was limited by idealised phase structures. The castability of A205 was determined using fluidity and hot tearing experiments. The better than expected castability was attributed to enhanced feeding brought about by the globular structure of A205.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):