Activation of slip and enhanced ductility in as-extruded Mg-Gd-Y-Nd alloys through Si addition
Activation of slip and enhanced ductility in as-extruded Mg-Gd-Y-Nd alloys through Si addition
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DOI：
10.1016/j.msea.2021.140736
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发表时间：
2021-02
期刊：
影响因子：
6.4
通讯作者：
Liqun Guan;Yun-lai Deng;An Luo;Xiao-bin Guo;Changping Tang
中科院分区：
文献类型：
--
作者：
Liqun Guan;Yun-lai Deng;An Luo;Xiao-bin Guo;Changping Tang
在Mg-8Gd-4Y-1ND合金中添加低成本的Si以改善其塑性。随着Si含量从0增加到1.0wt%，挤压态Mg-8Gd-4Y-1ND合金的延伸率从8.7%提高到17.1%。显微组织分析结果表明，随着Si含量的增加，GDSi和Y5Si3金属间化合物相的生成明显增多，促进了晶体结构的无序取向。由于Si在镁合金中起替代原子的作用，降低了第一本征层错(I1SF)能量，变形过程中激活了锥形位错，从而使{0001}镁基面偏离挤压方向，转变为无规则织构。在变形过程中激活锥体和基底滑移提供了更多独立的滑移系统，并导致更多的应力积累，超过了拉伸孪生的临界剪应力(CRSS)。同时激活的锥体<；c+a>；滑移和拉伸诱导孪晶改善了Mg-8Gd-4Y-1ND-1.0Si合金的塑性。
Low-cost Si was added to Mg-8Gd-4Y-1Nd alloys to improve their ductility. With the Si increased from 0 to 1.0 wt %, the elongation increased from 8.7% to 17.1% for as-extruded Mg-8Gd-4Y-1Nd alloys. Microstructures results indicated that the formation of GdSi and Y5Si3intermetallic phases increased significantly with the Si addition, which was shown to promote the random orientation of grain structures. As Si works as substitutional atoms in Mg alloys can decrease the first intrinsic stacking faults (I1SF) energy, the pyramidal <c+a> dislocation was activated during deformation, thus the {0001}Mgbasal plane deviate from the extrusion direction and alter to random textures. Activating both the pyramidal <c+a> and basal slip provided more independent slip systems during deformation and caused more stress accumulation, which exceeded the critical shear stress (CRSS) for tensile twinning. The simultaneous activation of the pyramidal <c+a> slip and tensile induced twinning improved the ductility of the Mg-8Gd-4Y-1Nd-1.0Si alloy.