Achieving ultra-high strength in Mg-Gd-Ag-Zr wrought alloy via bimodal-grained structure and enhanced precipitation
Achieving ultra-high strength in Mg-Gd-Ag-Zr wrought alloy via bimodal-grained structure and enhanced precipitation
复制标题
通过双峰晶粒结构和强化析出实现 Mg-Gd-Ag-Zr 变形合金的超高强度
DOI：
10.1016/j.jmst.2020.04.031
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发表时间：
2020-10-01
影响因子：
10.9
通讯作者：
Peng, Liming
中科院分区：
文献类型：
--
作者：
Zhang, Yu;Rong, Wei;Peng, Liming
MG-13.1GD-1.6AG-0.4 Zr（wt％）合金在350摄氏度下挤出在同心形上，或分别在500摄氏度的预热坯料上分别挤出，并在350度处死亡。相比之下，差分向热的合金形成了双峰粒的结构，由精细的等亚式的重结晶晶粒和粗伸长的未晶体晶粒组成，bar0> // a> // ED纹理上的<01（1）。降低热挤出的合金在排列后衰老后的沉淀量密度高于相比挤出的同伴。此外，在衰老之前，通过冷滚动进一步增强了差异热合金的降水。最后，合金通过差分向热挤压，冷滚动和老化获得了421 MPa的室温拉伸强度，最终的拉伸强度为515 MPa，主要归因于双峰螺旋结构的耦合加强和增强的降水量。合金的强度明显高于以前报道的具有相似成分的MG-GD（-y） - 挤出合金的强度，并且与其他高强度MG锻造合金相当。研究结果表明，差异热挤出加应变老化是一种适合实现年龄耐年龄毫克合金强度的方法。 （c）2020年由Elsevier Ltd代表材料科学技术杂志编辑办公室出版。
Mg-13.1Gd-1.6Ag-0.4 Zr (wt%) alloy was either iso-thermally extruded at 350 degrees C or differential-thermally extruded with respectively pre-heated billet at 500 degrees C and die at 350 degrees C. The iso-thermal extrusion leads to a near fully recrystallized structure and a [0001]//ED (extrusion direction) texture. In contrast, the differential-thermally extruded alloy develops a bimodal-grained structure composed of fine equiaxed recrystallized grains and coarse elongated unrecrystallized grains with a < 01 (1) over bar0 >//ED texture. The differential-thermally extruded alloy has a higher number density of precipitates after post-extrusion ageing than that of the iso-thermally extruded counterpart. Moreover, precipitation in the differential-thermally extruded alloy is further enhanced with cold rolling before ageing. Finally, the alloy obtains room temperature tensile yield strength of 421 MPa and ultimate tensile strength of 515 MPa via differential-thermal extrusion, cold rolling and ageing, mainly ascribed to the coupled strengthening from the bimodal-grained structure and enhanced precipitation. Strength of the alloy is noticeably higher than those of Mg-Gd(-Y)-Ag extruded alloys with similar compositions reported previously and is comparable to those of other high-strength Mg wrought alloys. The findings suggest that differential-thermal extrusion plus strain ageing is a suitable approach for achieving high strength in age-hardenable Mg alloys. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.