(湖南大学 材料科学与工程学院，长沙 410082)
摘 要: 探讨采用小异速比多道次异步轧制技术提高AZ31镁合金板材室温成形性能的可行性，研究异步轧制板材微观组织的特点、形成机理及其与成形性能间的内在联系。结果表明：多道次异步轧制所累积的剪切应变能有效促进压缩孪晶的交互作用，细化合金晶粒组织，削弱(0002)基面的织构强度；异步轧制AZ31镁合金板材后续退火处理后的室温伸长率和Erichsen值分别可达32%和6.14 mm；(0002)基面织构减弱和塑性应变比的降低是板材室温成形性能提高的根本原因。
关键字: AZ31镁合金；异步轧制；织构；孪晶；成形性能
magnesium alloy produced by differential speed rolling
（School of Materials Science and Engineering, Hunan University, Changsha 410082, China）
Abstract:To explore the possibility for enhancing the room temperature formability of AZ31 magnesium alloy sheets by multiple pass differential speed rolling(DSR) technic with small-speed ratio, the characteristic of microstructures and formation mechanisms for DSRed sheets were studied, and the intrinsic relationship between the microstructure and formability was discussed. The results show that the accumulated shear strain induced by multiple pass differential speed rolling promotes the interaction of compression twins. Furthermore, fine-grained microstructure and weakened (0002) basal texture can be achieved. A higher ductility with elongation of 32% and an evidently enhanced press formability with Erichsen value of 6.14 mm at room temperature are presented for as-DSRed/annealed specimen. The weakened (0002) basal texture intensity and lower plastic strain ratio are thought to be mainly responsible for the enhancement of room temperature formability.
Key words: AZ31 magnesium alloy; differential speed rolling; texture; twins; formability
