多道次等径角轧制对AZ31镁板组织性能的影响

Microstructures and Mechanical Properties of AZ31 Magnesium Alloy Sheet Processed by Multi-pass Equal Channel Angular Rolling

对AZ31镁合金进行多道次等径角轧制,并分析其微观组织、宏观织构和室温力学性能.结果表明,随着轧制道次的增加,板材的晶粒组织出现交替细化与粗化的现象,并直接影响板材后续退火组织的大小和均匀性.由于累积剪切变形的作用,等径角轧制后板材的基面织构明显弱化.七道次等径角轧制后基面极轴出现沿轧向分离,板材屈服强度降低约54%,而伸长率提高约43%.基面织构弱化和晶粒细化是等径角轧制板材塑性提高的主要原因.

AZ31 magnesium alloy sheets were prepared by multi-pass equal channel angular rolling （multi-pass ECAR）. The microstructure, texture and tensile properties were investigated. The results have shown that the grains in the sheets are processed alternatively with refined and coarse multi-pass ECAR, which has a great effect on the grain size and the homogeneity in the sheets after annealing. The significant weakening of basal texture is due to the accumulative shear strain. After ECARed for 7 passes, the basal poles split along the rolling direction. The yield strength decreased by about 54 %, and the elongation increased by about 43 %. The improvement of the ductility of the ECARed sheets is mainly related to the weakening of basal texture and the refinement of grain size.