CONSTITUTIVE-EQUATIONS FOR HIGH-TEMPERATURE FLOW-STRESS OF ALUMINUM-ALLOYS

Constitutive equations for the relationship between stress, strain, st rain rate, and temperature are an essential input for modelling thermo mechanical processing. Hot plane strain compression testing was used t o deform commercial purity aluminium, Al-1Mn, and Al-1Mg alloys at tem peratures of 300, 400, and 500 degrees C and equivalent strain rates o f 0.25, 2.5, and 25 s(-1), to an equivalent strain of 2. Flow stress d ata obtained from these tests were analysed using the Sah et al, and h yperbolic sine forms of relationships. Values of constants in the cons titutive equations were obtained and were shown to provide an accurate description of the experimental stress-strain curves, including the e ffect of temperature rise due to deformational healing and the effect of changing strain rate. The application and limitations of the relati onships are discussed. (C) 1997 The Institute of Materials.