热轧变形Mg-1.5Zn(-0.2~1.0)Gd合金再结晶组织及织构演变规律研究  

Recrystallization and Texture Mechanism of Hot Rolled Mg-1.5Zn-(0.2~1.0)Gd Alloy

作　　者：蔡正旭 Cai Zhengxu(China Aluminum Materials Application Research Institute Co.,Ltd.,Beijing 102209,China)

机构地区：[1]中铝材料应用研究院有限公司,北京102209

出　　处：《稀有金属》2022年第5期581-588,共8页Chinese Journal of Rare Metals

基　　金：国家重点研发计划“稀土新材料”重点专项(2021YFB3501000);中铝启明星项目(MX1991)资助。

摘　　要：研究了稀土Gd元素对变形Mg-1.5Zn合金热轧及退火组织及织构的影响规律。结果表明:稀土Gd元素加入Mg-1.5Zn合金中,经过热变形及后续退火处理,织构得到明显弱化并且沿着横向(TD)方向发生分裂,随着合金中Gd元素含量的增加,偏转的角度有所减小。当Gd元素含量为0.2%时,Mg-1.5Zn-0.2Gd合金的基面织构强度最大值为2.3,并且合金的宏观织构特征为c轴沿轧板TD方向偏转大约40°;随着Gd元素含量的增加,合金基面织构强度最大值有所增加,但最大强度仍小于2.8,c轴沿轧板TD方向角度逐渐减小,偏转大约30°。进一步研究表明,含稀土的细小第二相粒子是影响镁合金再结晶过程的主要因素,稀土第二相粒子弥散分布在原始晶界处,拖拽住原始大角度晶界的迁移,抑制了具有基面取向的晶粒形成,有效地控制了合金的基面织构,为具有随机取向的晶粒形核、长大提供了有利条件,从而使合金织构取向随机分布。然而,随着稀土Gd元素含量的增加,导致含稀土的第二相尺寸增大,对合金原始大角度晶界迁移的阻碍作用减弱,因此合金织构强度有所增加。With the development of automobile,3C electronics and aerospace,the demand of lightweight becomes more and more important.Rare Earth elements can change or weaken the basic surface texture of magnesium alloy,improve the forming ability of magnesium alloy at room temperature and help to expand the application range of magnesium alloy.Gd addition in Mg-Zn alloys can change the recrystallization process and effectively modify the basal plane texture during rolled and subsequently annealed.The main reason affecting the crystallization process is the very fine particles,which include Mg,Zn,Gd,precipitated on grain boundary restricts high angle grain boundaries migration,and inhibit basal plane texture formation.The grain with random orientation nucleation and growth when the very fine particles restrict high angle grain boundaries migration,resulting in the random texture of Mg-Zn-Gd alloys.Four magnesium alloys denoted as Mg-1.5Zn,Mg-1.5Zn-0.2Gd,Mg-1.5Zn-0.5Gd and Mg-1.5Zn-1.0Gd were prepared in this study.The alloys were prepared with high purity Mg(99.9%),Zn(99.9%),and Mg-30%Gd by vacuum melting.Ingots were prepared by pouring the melt into a preheated steel mold.The ingots were homogenized at 450℃for 12 h and then quenched in water.The ingots were subsequently machined to slabs with a dimension of 120 mm×90 mm×10 mm.The slabs were rolled to sheets with a final thickness of 1 mm at a reduction of 15%~20%per pass.After each pass,the sheets were reheated to 450℃and held for 15 min to maintain a consistent rolling temperature.The study of deformation and recrystallization of Mg-Zn-Gd alloy showed that the macrotexture of Mg-Zn alloy could be effectively changed by adding different content of rare earth Gd into Mg-1.5Zn alloy,the strength of the basic plane texture of the original magnesium alloy was weakened,which was greatly different from that of the general magnesium alloy.A large number of studies on the recrystallization behavior of magnesium alloys showed that neither dynamic recrystallization nor static r

关 键 词：镁合金 GD 再结晶 MgZnGd粒子 织构 

分 类 号：TG111[金属学及工艺—物理冶金]