Effects of nanoprecipitates and LPSO structure on deformation and fracture behaviour of high-strength Mg-Gd-Y-Zn-Mn alloys
Effects of nanoprecipitates and LPSO structure on deformation and fracture behaviour of high-strength Mg-Gd-Y-Zn-Mn alloys
复制标题
纳米沉淀和LPSO结构对高强Mg-Gd-Y-Zn-Mn合金变形和断裂行为的影响
DOI：
10.1016/j.matchar.2020.110396
复制
发表时间：
2020-07
影响因子：
4.7
通讯作者：
Liming Peng
中科院分区：
文献类型：
--
作者：
Ning Su;Xiaoyu Xue;Hui Zhou;Yujuan Wu;Qingchen Deng;Kun Yang;Qiang Chen;Bin Chen;Liming Peng
在这项工作中，通过热挤压和随后的时效开发了一种高强度 Mg-12Gd-2Y-1Zn-Mn 合金，其极限拉伸强度为 509 MPa，室温拉伸断裂伸长率为 5%。在拉伸过程中对挤压态和峰值时效合金的裂纹萌生和早期扩展进行了逐步观察。结果表明，未DRX处理的粗晶粒中细晶界滑动和多个非基础滑移系统的激活是挤压态合金的主要变形机制，最终导致裂纹萌生和扩展。峰值时效处理后，双峰晶粒内形成致密的β'析出物，导致拉伸过程中变形机制以及裂纹萌生和扩展行为发生变化。由于β'相的析出对位错迁移率的阻碍作用，抑制了晶界滑动，提高了晶界强度。因此，粗大未DRX晶粒中的无基底滑移和横向滑移成为裂纹扩展的主要作用。晶内 LPSO（长周期堆叠有序）相可以抑制挤压态合金和峰值时效合金中的裂纹萌生和扩展。对于挤压态合金晶界处较厚的LPSO相，它在一定程度上抑制了裂纹的扩展。而挤压峰时效合金晶界处的厚变形LPSO相随着拉伸应变的增加更容易引起裂纹萌生。
In this work, a high-strength Mg-12Gd-2Y-1Zn-Mn alloy with an ultimate tensile strength of 509 MPa and a fracture elongation of 5% at room temperature tensile was developed by using hot extrusion and subsequent ageing. Progressive observations of crack initiation and early propagation of the as-extruded and peak-aged alloys were conducted during the tensile process. The results show that the activation of fine-grain boundary sliding and multiple non-basal slip systems in coarse unDRXed grains is the dominant deformation mechanisms of the as-extruded alloy, which eventually lead to crack initiation and propagation. After peak-ageing treatment, dense β′ precipitates are formed within the bimodal grains, resulting in changes in deformation mechanisms and crack initiation and propagation behaviours during the tensile process. The grain boundary sliding is suppressed and the grain boundary strength is enhanced due to the precipitation ofβ′ phases on the hindering effect of dislocation mobility. Therefore, no-basal slip and cross-slip in coarse unDRXed grains become the major roles in crack propagation. The intra-grain LPSO (long-period stacking ordered) phase can suppress crack initiation and propagation in both as-extruded and peak-aged alloys. For the thick LPSO phase at the grain boundaries of the as-extruded alloy, it inhibits crack propagation to some extent. While the thick-deformed LPSO phase at the grain boundaries of the extruded-peak-aged alloy more easily causes crack initiation with increasing tensile strains.
登录
查看更多内容
时效%20行为%20of%20挤压%20Mg—8.2Gd—3.8Y—1.0Zn—0.4Zr%20(wt.%)%20合金%20含%20LPSO%20相%20和%20γ%20—析出物
影响因子：
4.6
作者：
Xu C;Nakata T;Qiao XG;Zheng MY;Wu K;Kamado S
通讯作者：
Kamado S
影响因子：
1.2
作者：
T. Kawabata;D. Nakagawa;Seiji Saikawa;J. Nakamura;S. Ikeno;K. Matsuda
通讯作者：
T. Kawabata;D. Nakagawa;Seiji Saikawa;J. Nakamura;S. Ikeno;K. Matsuda
影响因子：
9.4
作者：
Pineau, A.;Benzerga, A. A.;Pardoen, T.
通讯作者：
Pardoen, T.
影响因子：
9.4
作者：
Liu, H.;Gao, Y.;Nie, J. F.
通讯作者：
Nie, J. F.
影响因子：
9.8
作者：
Stanford, N.;Barnett, M. R.
通讯作者：
Barnett, M. R.