交叉轧制对ZK60镁合金组织演变和性能的影响

Effects of cross rolling on microstructure evolution and properties of ZK60 magnesium alloy

研究了轧制方式对ZK60镁合金组织与织构的影响规律,同时通过对退火后板材进行室温拉伸试验研究了其力学性能。经过交叉轧制的镁合金板材由于二次孪晶的生成及非基面滑移系的启动促使再结晶程度增大,晶粒细化效果显著,退火后平均晶粒尺寸达到6.43μm。同时交叉轧制会迫使晶粒向TD方向旋转,从而降低织构强度,改变织构类型。相比于单向轧制,交叉轧制后板材的平均抗拉强度和伸长率分别提高到321 MPa和25.7%,伸长率提高了近50%;塑性应变比、平面各向异性指数、屈强比等指标也得到了改善。结果表明,交叉轧制可有效调控镁合金板材组织及其均匀性、提高力学性能和成形性能。

The effects of rolling mode on microstructure and texture of ZK60 magnesium alloy were studied,and the mechanical properties were studied with tensile test of annealed sheets at room temperature. It shows that the dynamic recrystallization degree of magnesium alloy with cross rolling increases due to the generation of second twin and the start of non-basal slip system,resulting in obvious grain refinement,and the average grain size of annealed sheets reaches to 6. 43 μm. What＇ s more,the grain rotation orientation is forced to TD by cross rolling,resulting in the reduce of texture intensity and the change of texture type. Compared with normal rolling,the average tensile strength and elongation of the sheet after cross rolling are improved to 321 MPa and 25. 7%,respectively,the elongation increases by nearly 50% especially. The plastic strain ratio,the plane anisotropy index and the yield ratio of ZK60 alloy are also improved. The results show that cross rolling is an effective way to regulate the uniformity of magnesium alloy sheet microstructure and improve mechanical properties and formability of the alloy.