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为了研究挤压态AZ31B镁合金在高应变速率下的拉压不对称性,对挤压态AZ31B镁合金进行了织构分析。采用分离式Hopkinson压杆和反射式拉杆装置分别沿挤压方向和垂直挤压方向进行了动态压缩和拉伸试验,应变速率范围在500～2650s-1之间。结果表明,由于在挤压过程中形成了基面织构,沿挤压方向压缩时,拉伸孪晶{1012}<1120>容易启动,屈服强度对应变速率不敏感,且屈服强度较低;沿挤压方向拉伸时,拉伸孪晶不能启动,压缩孪晶{1011}<1120>和非基面滑移是其主要的塑性变形机制,合金屈服强度较高;合金在压缩和拉伸时表现出很强的拉压不对称性,压缩屈服强度与屈服强度的比值约为0.30。垂直于挤压方向拉伸和压缩时,没有表现出拉压不对称性。
In order to study the tension and compression asymmetry of extruded AZ31B magnesium alloy under high strain rate, texture analysis of extruded AZ31B magnesium alloy was carried out. Dynamic compression and tensile tests were carried out in the directions of extrusion and vertical extrusion respectively with split Hopkinson bar and reflective bar device at strain rates ranging from 500 to 2650s-1. The results show that the tensile twins {1012} <1120> are easy to start due to the formation of the base texture during the compression process. The yield strength is not sensitive to the strain rate and the yield strength is low. Tensile twins can not be started when stretched along the extrusion direction. Compression twins {1011} <1120> and non-basal slides are the main mechanisms of plastic deformation. The yield strength of the alloy is higher. When the alloy is compressed and stretched Show a strong tension and compression asymmetry, compression yield strength and yield strength ratio of about 0.30. Tensile and compression asymmetry was not shown when stretched and compressed perpendicular to the direction of extrusion.