Light Weighting of Structural Automotive Components Using High Strength Powder Metallurgy Aluminum Alloys

The intense effort by automotive companies to improve gas mileage and meet mandated CAFÉ Standards is aided by enabling vehicular mass reduction technologies. One area of such research is the application of appropriate powder metallurgy (PM) materials such as the alloys of aluminum, titanium, and magnesium. Each material option presents certain challenges that need to be overcome when manufacturing components for high volume and cost sensitive applications. Aluminum alloys produced by the PM technology have been used for several decades, but primarily in relatively low-stress components. The Al-4%Cu alloy has been the most widely-used PM material for over two decades in the form of automotive camshaft caps. This material offers yield strength and ultimate tensile strength values near 160 and 200 MPa, respectively. Heat treatment permits attainment of higher strength values, but sometimes with the accompanying embrittlement. This paper discusses process and alloy development work on PM aluminum alloys, which seeks to produce components with yield strength values of over 300 MPa, along with reasonable ductility. These components can replace many wrought, cast, or PM steel components with a reduction in mass of at least 50%.

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