【摘要】 塑性较差的六方结构镁合金轧制时易出现裂纹,尤其是在1mm以下薄板带的终轧阶段。其原因是在较低温度下基面取向晶粒内形成的切变带不易扩展所致。研究了MB1,AZ31(MB2 )镁合金在热模拟条件和实验室热轧过程中利用静态再结晶改善形变组织、细化晶粒、提高成形性的规律。实验表明,在选择的多道次轧制退火工艺下可顺利轧出0 3mm厚的薄板带,得到平均尺寸～7μm的等轴细晶。热模拟条件下得到的形变温度、形变量和形变组织的关系可帮助确定实际生产轧制过程中各道次轧制的温度。织构测定表明,各阶段退火前后都得到强的基面织构。终轧阶段无法利用{ 10 12 }拉伸孪晶的静态再结晶细化晶粒,而只能利用压缩孪晶扩展的切变带的再结晶细化晶粒。本文对轧制时利用动、静态再结晶细化晶粒的潜力及工艺优化进行了讨论。更多还原

【Abstract】 In the process of rolling for magnesium alloys cracking often appears when the thickness of sheets is below 1mm. This is due to the un-sufficient plastic deformation localized in shear bands formed in basal oriented grains at low temperatures. The two types of magnesium alloys were successfully rolled to the thickness of ～0.3mm by short time pass interval annealing.The microstructure and texture evolutions were examined by SEM and XRD. In addition, thermal simulation was conducted to reveal the relationship between microstructures and deformation temperatures. It is shown that at the later stage of rolling compression twins or shear bands are formed inevitably and short time annealing leads to grain refinement and improves formability. The grain refinement is discussed in terms of dynamic recrystallization and static recrystallization.更多还原