Study On Microstructure And Hot-deformation Behavior Of AZ31 Magnesium Alloy

The data about testing was gotten by isothermal compression testing method with Gleeble-1500 thermal simulator. The deformation behaviors, evolution behaviors of the microstructure and processing maps for the AZ31 magnesium alloy have been investigated. The interdependences of flow stressσ, strain rateεand deformation T for the alloy have been studied with the aids of regression analysis. The restoration mechanisms of the alloy at high temperatures have also been studied with the aids of the EBSD and OM. At last, the processing maps for the alloy have been drawn with the matlab software and have been analyzed in detail. The main contents are as follows:â‘ A near steady plastic flow of the AZ31 magnesium alloy was confirmed during isothermal compression deformation in the range of 200℃～450℃and 0.001-1～1-1.The flow stress increases with decreasing of deformation temperature and increasing of strain rate. The stress is sensitive to rate positively. So the deformation temperature and strain rate were major factors for process-control.â‘¡There is the process of hot activation under high temperature deformation for AZ31 magnesium alloy. The interrelations of flow stress, strain rate and deformation temperature can be described by a hyperbolic sine function for the alloy during the deformation process. The equation isε=1.5372×10¹¹ [sinh(0.0283σ)]^4.314 exp(-145.89/(RT))â‘¢The characteristic of deformation microstructure at high temperatures and various strain rates.AZ31 magnesium alloy have been studied. The crystal grain raise with the increase of temperatures at the same strain rates.T>400℃, the crystal grain would be coarsened. The crystal grain were non-unioform with the increase of strain rates at the same temperatures.With the raise of strain rates and temperatures,the base extremal became weaken.â‘£The orientation of dynamic recrystallization grains and base extremal were closed.The tures that small angle exist could indicate deformation mechanism still worked.⑤The process of hot deformation in the temperature range and different strain rate can be attained by the maps.which is hot deformation temperature was 623⁶73K and strain rates was 0.001^-10.003s^-1.The instability zones of flow behaviour can be recognized by the maps.