Influence of Strain Rate and Temperature on the Compressive Deformation of a Eutectic Al-Si Alloy Based Composite Reinforced with -Si3N4 Whisker

Abstract

The compressive properties characterized as a function of the true stress-strain response of -Si3N4 whisker reinforced 4032 aluminum alloy composite were examined at strain rates ranging from 10-3 to 100s-1 in the temperature interval 500~620oC. The effect of compressive deformation parameters such as strain rate and temperature on the mechanical behavior was systematically investigated. The strain rate sensitivity exponent and activation energy were calculated. The activation energy is 126 KJmol-1 at 500oC to 540oC, close to that for lattice self-diffusion in aluminum (142KJmol-1), and is 210 KJmol-1 at 540oC to 580oC ( =0.37s-1). The compressive deformation behavior of the composite can be described quantified by the Zener-Hollomon parameters (Z) for the solid state and the Non Newton-fluid for the semi-solid state of the composite. It is demonstrated that a linear equation of the logarithmic Z fits the flow stress of the composite at elevated temperatures. The compressive deformation mechanisms of the -Si3N4w/4032Al composite were discussed preliminarily.