变形Mg-1.5Zn-0.2Gd合金退火过程中组织与织构演变过程  

Evolutions of Microstructure and Texture of Rolled Mg-1.5Zn-0.2Gd Alloy During Hot Rolled and Subsequently Annealed

作　　者：蔡正旭[1] 唐荻[1] 江海涛[1] 马昭[1] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083

出　　处：《材料工程》2014年第7期44-49,共6页Journal of Materials Engineering

基　　金：国家"十二五"镁合金支撑项目课题三--镁合金板带高效低成本轧制技术开发(2011BAE22B00)

摘　　要：研究了变形Mg-1.5Zn-0.2Gd合金在热轧和退火过程中的显微组织、织构以及室温成形性能。结果表明:Mg-1.5Zn-0.2Gd合金经过热轧、退火后,其织构得到明显弱化并且沿着TD方向发生分裂,使得合金在室温下具有较高的断后伸长率和成形能力。450℃热轧后合金的基面织构强度最大值为3.4,RD方向上伸长率仅为6.7%;然而,合金经过350℃/60min退火后基面织构强度明显降低,最大值仅为2.3,并且基面织构沿着TD方向发生分裂,RD方向上伸长率达到26.7%。EBSD研究表明,稀土Gd元素溶入合金中,阻碍了热轧过程中动态再结晶的发生,在随后的退火过程中,非基面取向晶粒在原始大角度晶界位置形核长大,这是Mg-1.5Zn-0.2Gd合金织构得到优化的关键原因。Microstructure, texture and stretch formability of roiled Mg-1.5Zn-0.2Gd alloy during hotroiling and subsequently annealing were investigated. The results show that Mg-1.5Zn-0.2Gd alloyafter hot roiling and annealing exhibits excellent elongation and high stretch formability, which is attributed to the reduction in basal texture intensity and the split of basal plane. After rolling at 450℃,the maximum texture intensity of the alloy is 3.4 and the elongation is 6.7 % in RD direction. Howev-er, after annealing at 350℃ for 60min, the texture intensity of the alloy decreases and the maximumintensity is 2. 3, and basal texture is tilted from TD, which result in the elongation increases to26.7% in RD direction. EBSD analysis indicates that the addition of Gd hinders dynamic recrystalliza-tion （DRX） during hot rolling process. The nucleation and growth of non-basal orientation grains oc-cur at the original high angle grain boundaries during the subsequent annealing, which plays an impor-tant role in the weakened basal texture intensity of the Mg-1.5Zn-0.2Gd alloy.

关 键 词：镁合金 织构 再结晶 

分 类 号：TG146.2[一般工业技术—材料科学与工程]