Hardening evolution of AZ31B Mg sheet
Hardening evolution of AZ31B Mg sheet
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DOI：
10.1016/j.ijplas.2006.03.005
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发表时间：
2007-01-01
影响因子：
9.8
通讯作者：
Wagoner, R. H.
中科院分区：
文献类型：
--
作者：
Lou, X. Y.;Li, M.;Wagoner, R. H.
对O状态AZ 31 B镁合金板材在大应变拉压和简单剪切下的单调和循环力学行为进行了测试。金相，声发射（AE），和纹理测量显示在面内压缩和随后的拉伸时untwinning孪生，产生不对称的屈服和硬化演变。一个工作模型的变形机制与结果和文献相一致的基础上，主要是基础滑移的初始张力，孪生初始压缩，和untwinning拉伸压缩。孪晶的激活应力大于非孪晶的激活应力，这可能是因为需要成核。累积硬化的增加使孪晶形核应力增大，但对非孪晶应力影响不大。多周期变形趋于饱和，较大的应变周期饱和更慢。一种新的分析饱和循环的基础上被用来估计与孪生硬化效应的相对大小。对于4%的应变范围，孪晶对滑移的阻碍强度为3 MPa，约为孪晶形成所引起的织构硬化量（10 MPa）的1/3。孪晶与非孪晶的激活应力之差（11 MPa）与织构硬化的大小相同。(c)2006爱思唯尔有限公司保留所有权利。
The monotonic and cyclic mechanical behavior of O-temper AZ31B Mg sheet was measured in large-strain tension/compression and simple shear. Metallography, acoustic emission (AE), and texture measurements revealed twinning during in-plane compression and untwinning upon subsequent tension, producing asymmetric yield and hardening evolution. A working model of deformation mechanisms consistent with the results and with the literature was constructed on the basis of predominantly basal slip for initial tension, twinning for initial compression, and untwinning for tension following compression. The activation stress for twinning is larger than that for untwinning, presumably because of the need for nucleation. Increased accumulated hardening increases the twin nucleation stress, but has little effect on the untwinning stress. Multiple-cycle deformation tends to saturate, with larger strain cycles saturating more slowly. A novel analysis based on saturated cycling was used to estimate the relative magnitude of hardening effects related to twinning. For a 4% strain range, the obstacle strength of twins to slip is 3 MPa, approximately 1/3 the magnitude of textural hardening caused by twin formation (10 MPa). The difference in activation stress of twinning versus untwinning (11 MPa) is of the same magnitude as textural hardening. (c) 2006 Elsevier Ltd. All rights reserved.