Grain Refinement and Texture Evolution of Mg-Gd-Y-Zn-Zr Alloy Processed by Repetitive Usetting-extrusion at Decreasing Temperature
Grain Refinement and Texture Evolution of Mg-Gd-Y-Zn-Zr Alloy Processed by Repetitive Usetting-extrusion at Decreasing Temperature
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DOI：
10.1016/s1875-5372(18)30144-9
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发表时间：
2018-05-01
影响因子：
0.7
通讯作者：
Yu Jianmin
中科院分区：
文献类型：
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作者：
Du Yue;Zhang Zhimin;Yu Jianmin
对均匀化的Mg-13Gd-4Y-2ZN-0.5Zr(wt%)合金进行了从480℃到370℃的重复顶粗挤压(RUE)工艺，研究了RUE工艺过程中合金的组织和织构的发展。结果表明，随着累积应变的增加和温度的降低，平均晶粒度减小。经过6道次的累积应变为8.4次后，获得了平均晶粒度为3.4gm的均匀超细晶组织。非连续动态再结晶(DDRX)和连续动态再结晶(CDRX)的复杂组合导致了组织的细化。片层长周期堆积有序相(LPSO)的扭结通过诱导扭结带中的再结晶细化粗晶，在细化晶粒过程中起着重要作用。经过1次RUE后，获得了较强的基面织构。随着RUE道次的增加，织构逐渐减弱，这是动态再结晶(DRX)和RUE加工过程中加载方向(轴向和径向)交替变化的共同作用的结果。
A homogenized Mg-13Gd-4Y-2Zn-0.5Zr (wt%) alloy was subjected to a repetitive upsetting-extrusion (RUE) process at decreasing temperature from 480 degrees C to 370 degrees C. The microstructure and texture development of the alloy during the RUE process was investigated. The results show that average grain size decreases with increasing cumulative strain and decreasing temperature. Uniform ultrafine-grain structure with an average grain size of 3.4 gm is achieved after 6 passes, i.e., cumulative strain of 8.4. Grain refinement is induced by a complicated combination of discontinuous dynamic recrystallization(DDRX) and continuous dynamic recrystallization(CDRX). Kink of lamellar long period stacking order (LPSO) phases play an important role in the grain refinement through subdividing the coarse grains by inducing recrystallization evolved in the kink bands. After 1 pass of RUE, a strong basal texture is obtained. With increasing RUE passes, the texture is gradually weakened, which results from cooperative effect of dynamic recrystallization(DRX) and the alternative change of loading directions (axial and radial) during RUE processing.