循环交叉轧制对ZK60镁合金组织和性能的影响

Microstructure and Properties of ZK60 Magnesium Alloy with Circle Cross Rolling

通过采用循环交叉轧制（每轧一次旋转90°，4次叫一个循环）的方式，研究其对ZK60镁合金棒材组织和性能的影响。采用金相显微镜（OM），X射线衍射（XRD），电子扫描电镜（SEM），透射电镜（TEM），显微硬度仪，MTS801立式实验机研究了循环轧制后的组织、析出相、断口、织构、硬度和拉伸性能。结果表明：未变形的ZK60镁合金在温度降低的同时经过循环交叉轧制后晶粒从132Ixm细化到1．42μm，硬度提高了50％，屈服强度提高了135％，抗拉强度提高了45％，延伸率经过3道次轧制后从9％降到5．3％，4道次回升到7．5％，5到7次略微下降，8次上升到8．98％，9道次又下降了0．28％；在轧制过程中，析出相的数量随轧制道次的增加而增加，且弥散分布于晶粒内部和晶界，大幅提高了材料的力学性能；通过对轧制过程中织构的分析可得，4和8道次的织构强度相对较弱，与4和8道次延伸率的上升相协调，所以很好地证明了通过采用循环交叉轧制的方式能够显著提高了ZK60镁合金的力学性能，增加材料的组织均匀性和等轴性。

The effect of circle cross rolling （rotating 90°after a pass, 4 passes is a circle） on microstructure and properties of ZK60 magnesium alloy were investigated. Optical microscope （ OM ） , X-ray diffraction （ XRD ） , scanning electron microscopy （SEM） , transmission electron microscopy （TEM） , micro hardness tester and MTSS01 were used to research microstructure, precip- itates, fracture, texture, hardness and tensile property. The results showed that the grain size was reduced from 132 μm to 1.42 p,m, the hardness increased by 50% , the yield strength increased by 135% , the ultimate tensile strength increased by 45% , the e- longation decreased from 9% to 5.3% after 3 passes, it increased to 7.5% and 8.98% respectively after 4 and 8 passes, and de- creased slightly after 5 to 7 passes and 9 passes. The precipitates increased with the rolling passes, the texture intensity of 4 and 8 passes was relatively weakened, which proved that using cyclic cross roiling could improve the mechanical properties of ZK60 magne- sium alloy.