Influence of AZ31 sheet treated by cryogenic on punch shearing

深冷处理对AZ31板冲剪的影响（英文）

Punch shearing is used to form the part in the material process.Cryogenic treatment(CT)has active effect on local mechanical properties of steel,but it is still uncertain of the influence of CT on the properties of the magnesium alloy during punch shearing.In this work,the influence of AZ31 sheet treated by cryogenic on punch shearing was studied.Microstructures were observed with a ZEISS optical microscope,and mechanical properties,as well as shear properties were tested by tensile testing and punch shearing.The results show that the number of secondary phase increases and a large number of twins appear in the grains after CT.Meanwhile,the ultimate tensile strength(UTS),the ductility,and hardness of AZ31 are improved,while the yield strength(YS)decreases gradually during CT.During punch shearing,the shearing strength decreases,the rollover radius changes insignificantly,and the height of the burr on the edge of the cross section decreases.At the same time,a larger proportion of smooth zone on the cross section has been achieved.

冲剪成形作为一种材料加工方法,经常用于加工一些成品零件。深冷处理在改善钢的局部力学性能上有显著效果,但有关深冷处理对镁合金冲剪性能影响的研究较少。本文通过金相组织分析、拉伸、硬度测试和冲剪实验等,分析了深冷处理对AZ31板冲剪性能的影响。结果表明:深冷处理后组织中第二相数量增加,晶粒中出现大量孪晶。同时,AZ31镁合金的抗拉强度,延展性和硬度均得到改善,而屈服强度在深冷处理后有所降低。此外,经深冷处理后的AZ31镁合金板在冲剪过程中,剪切强度降低,圆角半径变化不明显,横截面边缘的毛刺高度降低,光亮带所占比例明显增加。