Investigating the flow curve of the AZ31 magnesium alloy at high temperature using the ring test

In the present study, a test procedure is proposed to investigate the flow curve of the AZ31 Mg alloy at elevated temperatures and both the temperature and strain rate affect on flow stress of AZ31 magnesium alloys. Experiments were carried out with the goal of obtaining flow curve of AZ31 at three different temperature and strain rates by using the ring test method. This work attempts to develop a model using genetic algorithm to predict the flow stress of AZ31 magnesium alloy for hot compression deformation test conditions. The testing machine was capable of doing the experiments in position and load control modes. The experiments were performed under isothermal condition with temperatures of 473, 493 and 513 K and strain rates of 0.025, 0.0025 and 0.00025 s-1.In the present investigation for three different temperatures and strain rates, 54 ring compression tests were carried out with different levels of reduction in height. Then each specimen was water cooled quickly to investigate the microstructure of AZ31 magnesium alloy by using optical microscope. The model used in the present study can predict the mean flow stress within an average error of 2.5% from the experimental data, using strain, strain rate and temperature as inputs. This model seems to have a great potential to employed in industries.

Keywords:

High temperature , Magnesium , AZ31 , Ring Test