Paper number 189

ISOTHERMAL CREEP RESPONSE OF AL-BASED MMCS UNDER TENSILE AND COMPRESSIVE LOADING

A.F. Whitehouse¹, H.M.A. Winand² and P.J Withers³

1Department of Engineering, University of Leicester
University Road, Leicester LE1 7RH, UK
2Department of Materials Science and Metallurgy, University of Cambridge
Pembroke Street, Cambridge CB2 3QZ, UK
3University of Manchester, Manchester Materials Science Centre,
Grosvenor Street, Manchester M1 7HS, UK

Summary

The isothermal creep response of various SiC reinforced powder-route Al-based composites were investigated at 270 and 300 °C in both tension and compression. In tension, microstructural damage was found to occur early during the deformation for large reinforcement size, in the form of cavities, preventing a true steady state from being reached. This was confirmed using instantaneous Poisson ratio measurement. The extent to which the damage dominated the tensile response was highly dependent on the reinforcement size. Minimum strain rates in tension were compared with strain rates in compression at similar composite strains. For 20 µm particulate reinforcement, strain rates during compression were lower than the minimum strain rates measured during tension. Creep resistance was found to increase with decreasing reinforcement size and increasing volume fraction in both tension and compression.

Keywords

isothermal creep, tensile, compressive, damage, discontinuous, Al.