Constitutive Analysis to Predict High-Temperature Flow Stress of 25vol% B 4 Cp/2009Al Composite

Abstract

Isothermal compression tests of 25vol% B4Cp/2009Al composite have been carried out at temperatures ranging from 300 º C to 500 º C and strain rates ranging from 0.001 s-1 to 1 s-1. The results show that high-temperature flow stress of the composite decreases with the increase of deformation temperature and the decrease of strain rate. The flow stress has been corrected by friction and the friction corrected stress is lower than experimental values. The influence of friction becomes more obvious with decreasing temperature and increasing strain rate. Then a constitutive equation considering the effect of strain on material constants (i.e. α, n, Q and A) is developed on the basis of Arrhenius type equation. Compared with the experimental results, the flow stress calculated by the constitutive equation possesses a high precision with the correlation coefficient of 0.992. Higher temperature and lower strain rate is beneficial to hot deformation of B4Cp/2009Al composite.