再结晶退火对Mg-1.5Y板材组织、织构及性能的影响

Effect of Recrystallization Annealing on Microstructure, Texture and Properties of Mg-1.5Y Alloy Sheet

利用十字交叉轧制工艺制备了Mg-1.5Y合金板材,研究了再结晶退火(475℃/15min)对其微观组织、宏观织构、力学性能及成形性能的影响。结果表明,退火促使轧制板材发生强烈的静态再结晶,形成均匀的等轴晶组织。轧制态板材呈现出近圆形-双峰织构分布特征,(0002)面极点由法向(ND)向轧制方向2(RD2)倾转大约±20o;再结晶退火后,基面极点沿轧制交角方向发生劈裂,形成蝴蝶状-多峰弱织构分布特征,且晶粒取向更加随机化,最大极密度由轧制态的5.0降低至2.8。退火态板材的断后伸长率、杯突值分别达到30.5%、4.4mm,相对于轧制态分别提高了63%、42%。

Mg-1.5 Y alloy sheet was prepared by cross-rolling technique. The effect of recrystallization annealing(475 °C/15 min) on microstructure, macro-texture, mechanical properties and stretch formability of Mg-1.5 Y alloy sheet was primarily studied. The results show that the uniform equiaxed grains form through strong static recrystallization after recrystallization annealing. The texture of as-rolled alloy sheet exhibits a subrotund-bimodal orientation distribution, and the basal-pole intensity peak tilts about ±20° from normal direction(ND) to rolling direction 2(RD2). The texture orientation distribution is more dispersed and randomized after recrystallization annealing. The basal-pole intensity peak splits along the direction of intersection angle between rolling directions and a butterfly-shaped multi-peaks weak texture orientation distribution finally forms. Besides, the maximum intensity of basal plane decreases from 5.0 to 2.8. The fracture elongation and index of Erichsen test of as-annealed alloy sheet are 30.5% and 4.4 mm, respectively, which is improved by 63% and 42% compared with as-rolled alloy sheet.