The project aim was to develop a lean method for bimetallic fuel pump bearing manufacture using powder metallurgy (PM), as an alternative to flame spraying. Specifically, the sintering and diffusion bonding of aluminum powder alloy to 30% leaded bronze included: • 'Press and sinter': AI-6%Si alloy. 7075 alloy (AI-5.5%Zn-2.5° oMg-1.6%Cu), \(\leq\)500 °C AI-8%Mg-4%Zn alloy, \(\leq\) 500 °C. • HIP (Hot Isostatic Pressing) - AI-6%Si alloy. • 'Hot compaction' - AI-8%Mg-4%Zn alloy. 'Press and sinter' of AI-6%Si alloy resulted in residual porosity and expansion during cooling, due to silicon density reduction during solidification. HIP enabled simultaneous compaction, sintering and diffusion bonding of AI-6%Si alloy to leaded bronze; bearing 'blanks' were manufactured, with an intermetallic layer (approximately 100\(\mu\)m) at the interface.'Press and sinter' of 7075 alloy resulted in swelling during transient liquid phase formation and residual porosity. However, using AI-8%Mg-4%Zn alloy this process demonstrated improvement, as it was closer to its solidus temperature at the chosen processing temperature. Test pieces and bearing 'blanks' were produced, with an intermetallic layer (approximately 20 \(\mu\)m) at the interface, of tensile strength > 20 MPa, superior to flame sprayed bearings. Further work involved optimising HIP and 'hot compaction' processing for batch production.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:629730 |
| Date | January 2014 |
| Creators | Poole, Andrew David |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/5500/ |
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