The effect of processing parameters on the microstructure and texture evolution of a cup-shaped AZ80 Mg alloy sample manufactured by the rotating backward extrusion
The effect of processing parameters on the microstructure and texture evolution of a cup-shaped AZ80 Mg alloy sample manufactured by the rotating backward extrusion
复制标题
加工参数对旋转反向挤压杯形AZ80镁合金样品显微组织和织构演变的影响
DOI：
10.1016/j.jallcom.2020.156264
复制
发表时间：
2021-02-15
影响因子：
6.2
通讯作者：
Zhang, Zhiming
中科院分区：
文献类型：
--
作者：
Che, Xin;Dong, Beibei;Zhang, Zhiming
旋转反向挤压（RBE）工艺在AZ80镁合金剧烈塑性变形（SPD）的基础上，具有生产高质量杯形镁合金件的巨大潜力。然而，关于RBE工艺的微观组织和织构发展的研究仍然非常有限。因此，在本工作中，AZ80镁合金杯形件的RBE工艺在573,613和653 K三种温度下进行，旋转转速分别为5、50和100。此外，还进行了常规反向挤压（CBE），即旋转转速N = 0。详细研究了旋转转速和加工温度对合金组织和织构演变的影响。结果表明，与CBE工艺相比，RBE工艺可以获得相对精细和均匀的组织。随着旋转转速的增加，样品的平均晶粒尺寸减小，动态再结晶率逐渐增加。随着温度的升高，杯状试样的晶粒尺寸逐渐增大，在N = 0和N = 5时，DRX分数也逐渐增大，而在N = 50和N = 100时，DRX分数基本不变。在573 K、N = 100条件下，晶粒尺寸最小为3.9 mm， DRX分数最大为99.2%。RBE过程中的晶粒细化主要是由连续DRX （CDRX）和不连续DRX （DDRX）两种变形机制决定的。降低变形温度可促进动态析出相（DP）的生成，增加旋转转速可减小动态析出相的尺寸，使未溶共晶相（EP）更加破碎。此外，在RBE过程中，增加旋转转速或温度可以有效地削弱CBE样品中表现出的强织构，因为新DRXed晶粒的比例更高，其取向比变形晶粒更具随机性。(C) 2020 Elsevier B.V.版权所有
The rotating backward extrusion (RBE) process is of great potential for producing the high qualitative cup-shaped AZ80 magnesium (Mg) alloy pieces based on the severe plastic deformation (SPD). However, researches on RBE process involving the microstructure and texture development are still pretty limited. Thus, in this work, the RBE process of AZ80 Mg alloy cup-shaped pieces was performed at three temperatures of 573, 613 and 653 K combining with three different rotating revolutions of 5, 50 and 100. Furthermore, the conventional backward extrusion (CBE), i.e. N = 0 in the rotating revolution, was also conducted for comparison. The effects of rotating revolution and processing temperature on the microstructure and texture evolution were studied in detail. The results showed that a relatively refined and homogeneous microstructure could be achieved by the RBE process compared with the CBE process. With the increasing rotating revolutions, the average grain size of the sample was decreased and the dynamical recrystallization (DRX) fraction was increased gradually. As the temperature increasing, the grain size of the cup-shaped samples was gradually increased, and the DRX fraction was also gradually increased for N = 0 and N = 5 samples, while it was almost unchanged for N = 50 and N = 100 samples. The smallest grain size of 3.9 mm and the largest DRX fraction of 99.2% were both obtained at 573 K with N = 100. The grain refinement during the RBE process was mainly caused by the DRX, which was determined by the deformation mechanism including the continuous DRX (CDRX) and discontinuous DRX (DDRX). Decreasing the deformation temperature could promote the generation of dynamic precipitates (DP), increasing rotating revolutions could reduce the size of the DP and make the undissolved eutectic phase (EP) more fragmented. In addition, the strong texture exhibited in the CBE samples could be effectively weakened by increasing the rotating revolution or temperature during the RBE process, owing to the higher proportion of new DRXed grains whose orientations were more random compared to the deformed grains. (C) 2020 Elsevier B.V. All rights reserved.