Abstract: The flow stress behaviors of AZ61 alloy has been investigated at temperature range from 523 to 673K with the strain rates of 0.001--1s-1. It is found that the average activation energy, strain rate sensitive exponent and stress exponent are di®erent at various deformation conditions changing from 143.6 to 176.3kJ/mol, 0.125 to 0.167 and 6 to 8 respectively. A flow stress model for AZ61 alloy is derived by analyzing the stress data based on hot compression test. It is demonstrated that the flow stress model including strain hardening exponent and strain softening exponent is suitable to predicate the flow stress. The prediction of the flow stress of AZ61 alloy has shown to be good agreement with the test data. The maximum differences of the peak stresses calculated by the model and obtained by experiment is less than 8%.

Key words: magnesium alloy, flow stress model, hot deformation,