Study On Microplastic Deformation Behavior Of High-strength Mg-Gd-Y-Zn-Zr Alloy

The effect of hot extrusion and heat treatment on microplastic behavior ofhigh-strength Mg-Gd-Y-Zn-Zr alloy containing LPSO was described in thispaper. The microplastic behavior was discussed using simple tension and cyclicloading and the evolution of the microstructure in microplastic was found in theresearch. The microplastic theory provided a basis of research of highdimensional stability magnesium.The microyield strength decreased by solution treatment, and increased byannealing treatment or aging treatment in the research. Solution treatment canmake most of the second phase at grain boundaries into the substrate, so strongpinning point which can block dislocation slip decreased and caused lowmicroyield strength. The precipitation in annealed alloy, called LPSO, can blockbasal slip significantly and cause high microyield strength. Peak-aged alloy hadvery high microyield strength because the tiny precipitation by aging treatmentcan block dislocation slip significantly. In the same condition, plasticdeformation increased by solution treatment and decreased by annealingtreatment or aging treatment. The anelasticity behavior was obvious in annealedalloy.T5aging treatment had a significant impact on Mg-9Gd-3Y-2Zn-0.4Zr-0.2Ca alloy. Microyield strength reached a maximum by aging88hoursupon when lots of precipitation formed. And there was less tiny precipitation inunderaged alloy and bigger precipitation in overaged alloy. In the samecondition, plastic deformation decreased by aging treatment. The anelasticitybehavior was obvious in overaged alloy. Microplastic behavior ofMg-Gd-Y-Zn-Zr alloy showed aeolotropy. Samples parallel to the direction ofextrusion had big microyield strength.