Influence of warm temperature (0.3-0.5Tm) uniaxial compression on the distribution of reinforcing particles in a 2124-Al/10%SiC MMC

Experimental work was carried out to study the influence of uniaxial compression tests, performed on a Gleeble 3500, on the distribution of reinforcing particles in SiC reinforced Al Metal Matrix Composites (MMCs). Al MMC powder (2124-Al with 10 vol. %SiC) was produced through blending in a high energy ball mill. Unreinforced 2124-Al and Al MMC powders were compacted at ambient temperature (i.e. cold compaction) and the green compacts were then sintered at 490°C for 1 hr. Warm temperature (280°C) uniaxial compression tests were performed on a Gleeble 3500 thermomechanical simulator at a strain rate of 5 s^-1, strain of 0.3 and a soaking time 20 minutes.

Microstructures of the uniaxially compressed 2124-Al with 10% SiC MMC revealed that deformation had an influence on the distribution of reinforcing particles. Reinforcing particles were only distributed inside 2124-Al grains that had undergone deformation (evident through change in shape of grains). This finding supports statements made in literature regarding the positive influence of deformation on the distribution of reinforcing particles. Engineering stress-strain curves showed that reinforcing 2124-Al with 10 vol. % SiC had a positive effect on flow stress as the 10%SiC MMC had a flow stress of 153 MPa while the flow stress of the unreinforced 2124-Al was 95 MPa. An improvement in hardness was also observed where the MMC had a higher hardness than the unreinforced Al alloy; further indicating that reinforcing the Al alloy improved properties. (paper)