脉冲电流轧制对AZ31镁合金微观组织与力学性能的影响

对比研究脉冲电流轧制工艺与温轧工艺对AZ31镁合金板材的力学性能、织构、微观组织与沉淀相等方面的影响。结果表明：脉冲电流具有促进冷轧AZ31镁合金低温再结晶能力的作用。脉冲电流轧制后的镁合金板材组织由细小的等轴再结晶粒与析出相构成,没有发现孪晶组织,并且完全再结晶,原始晶粒均被细小的再结晶晶粒取代,再结晶晶粒内的位错密度低。而温轧镁合金组织则由稍拉长变形孪晶、粗大的再结晶晶粒和析出相构成,再结晶的晶粒内位错密度高。两种轧制方式下的镁合金析出相均为Mg17Al12。脉冲电流轧制后镁合金的织构具有典型基面织构的特征,而脉冲电流轧制镁合金的织构则出现横向偏转;脉冲电流轧制后镁合金的屈服强度与伸长率均比温轧镁合金的大,但抗拉强度正好相反。

Effect of electropulsing rolling on mechanical properties and microstructure of AZ31 magnesium alloy

Electropulsing rolling （ER） and warm rolling （WR） processes were performed to roll AZ31 magnesium alloy sheets. Mechanical properties, microstructure and texture evolution of these specimens were investigated after rolling. The results indicate that electropulsing accelerates the recrystallization of AZ31 alloy sheets during hot rolling. After electropulsing rolling at a relatively low temperature, the microstructure of the sample shows fine equiaxed recrystallized grains with a lower density of dislocations and precipitates. In contrast, the microstructure of the sample after warm rolling shows elongated grain, numerous deformed twins, and a high density of dislocation and precipitates. Electropulsing rolling helps weaken the basal fiber texture. Although both the alloy sheets （ER and WR） have typical basal fiber texture, the maximum pole intensity of basal in ER sample is weaker. ER sheet has higher yield strength and elongation compared to WR sheet. As a promising technique, electropulsing rolling can be used to improve the microstructure and mechanical properties of materials.