A comparative study of cavitation characteristics in composite and 7475 aluminum alloy

Abstract

Recently, it has been demonstrated that many aluminum matrix composites with discontinuous SiC or Si[sub 3]N[sub 4] show superplastic behavior. In particular, it should be noted that some aluminum matrix composites show superplasticity at high strain rates (> 10[sup [minus]2] s[sup [minus]1]). It is well established that cavitation occurs during superplastic flow in a wide number of metallic materials. However, the cavitation behavior in superplastic metal matrix composites is not well understood. It is important to investigate characteristics of cavitation in metal matrix composites for superplastic forming applications. In this investigation, cavitation in a 20 vol% Si[sub 3]N[sub 4p]/Al-Mg-Si composite, which exhibits superplasticity at high strain rates, has been investigated and the data of the composite have been compared with those of the superplastic 7475 alloy which is a typical superplastic aluminum alloy.