Deformation mechanisms of Mg-Ca-Zn alloys studied by means of micropillar compression tests
Deformation mechanisms of Mg-Ca-Zn alloys studied by means of micropillar compression tests
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DOI：
10.1016/j.actamat.2021.117151
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发表时间：
2021-07-27
期刊：
影响因子：
9.4
通讯作者：
Zeng, Xiaoqin
中科院分区：
文献类型：
--
作者：
Wang, Jingya;Chen, Yiwen;Zeng, Xiaoqin
通过不同取向的单晶微柱压缩试验，测定了固溶体中Ca和Zn对镁合金基滑移、拉伸孪晶和锥体滑移临界分解剪应力的影响。溶质原子使基底滑移的CRSS提高到13.5 MPa，而锥体滑移的CRSS低于85 MPa，与纯Mg相比，显著降低了塑性各向异性。此外，孪晶成核和长大的CRSS非常相似（均为37 MPa），较大的CRSS值阻碍了孪晶在热机械加工过程中的生长。最后，发现了基底位错与柱位错之间的棱柱滑移和交叉滑移的证据。结果表明：Mg-Ca-Zn合金塑性各向异性的降低、不同滑移体系和交叉滑移的激活以及大CRSS促进孪晶生长的弱基底织构是提高合金塑性和成形性能的主要原因。(C) 2021材料学报Elsevier Ltd.出版。版权所有。
The effect of Ca and Zn in solid solution on the critical resolved shear stress (CRSS) of basal slip, tensile twinning and pyramidal slip in Mg alloys has been measured through compression tests on single crystal micropillars with different orientations. The solute atoms increased the CRSS for basal slip to similar to 13.5 MPa, while the CRSS for pyramidal slip was lower than 85 MPa, reducing significantly the plastic anisotropy in comparison with pure Mg. Moreover, the CRSSs for twin nucleation and growth were very similar (similar to 37 MPa) and the large value of the CRSS for twin growth hindered the growth of twins during thermo-mechanical processing. Finally, evidence of prismatic slip and cross-slip between basal and prismatic dislocations was found. It is concluded that the reduction of plastic anisotropy, the activation of different slip systems and cross-slip and the weak basal texture promoted by the large CRSS for twin growth are responsible for the improved ductility and formability of Mg-Ca-Zn alloys. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.