Measurement of Residual Stress in a Powder Metallurgy Aluminium–SiC Composite

Abstract

Powder metallurgy is a potentially attractive route for producing metal matrix composites. In order to optimize the mechanical properties and processing route, it is important to have knowledge of the internal stresses. Eight Al–SiC metal matrix composites were produced with two different aluminium matrices, two SiC dispersoids and two sintering processes. Residual strains were measured using neutron diffraction. The different sintering processes had little effect on the strains in the two phases, but differences were found for the different SiC dispersoids, with large SiC particles showing smaller strains when a pure aluminium powder was used for the matrix. For a commercial casting aluminium alloy matrix containing ∼11% Si, the measured strains were similar for both types of SiC particles. The results show that powder metallurgy is a promising route for producing metal matrix composites with controlled levels of residual stress.