Experimental Study on Constitutive Equation of AZ31 Magnesium Alloy Plastic Deformation at Elevated Temperature

摘要

Uniaxial compression tests of AZ31 magnesium alloy were performed to investigate the plastic deformation behavior in the temperature range from 523K to 673K and strain rate range from 0.001s-1 to 1s-1 by using thermal simulation machine Gleeble1500D. The influence of temperature, deformation strain rate and dynamic recrystallization (DRX) on the flow stress of AZ31 magnesium alloy was studied in detail. Power law was employed to describe the stress at peak and steady state. The hot deformation activation energy was 167kJ/mol at peak state and 142kJ/mol at steady state respectively. Two distinct approaches to modeling the flow stress in piecewise equation at elevated temperature were reviewed, in which one is dislocation density model and the other is curve description model. The prediction data by two models were both in good agreement with experimental data. The curve description model possesses preferable application in finite element analysis as it contains less parameters.