Microstructure evolution and mechanical properties of as-extruded Mg-Gd-Y-Zr alloy with Zn and Nd additions
Microstructure evolution and mechanical properties of as-extruded Mg-Gd-Y-Zr alloy with Zn and Nd additions
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DOI：
10.1016/j.msea.2017.12.070
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发表时间：
2018-01
期刊：
影响因子：
6.4
通讯作者：
Zijian Yu;Chao Xu;J. Meng;Xuhu Zhang;S. Kamado
中科院分区：
文献类型：
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作者：
Zijian Yu;Chao Xu;J. Meng;Xuhu Zhang;S. Kamado
研究了添加Zn和Nd的Mg-11.5Gd-4.5Y-0.3Zr（wt%）合金挤压态的组织演变和力学性能。Zn的加入抑制了动态再结晶（DRX），这是由于长周期堆垛有序（LPSO）相的存在。Nd的加入促进了Mg 5 RE（RE：稀土）相的析出。热挤压前致密分布的Mg 5 RE相的存在促进了后续热挤压过程中的动态再结晶，导致晶粒细化。Mg 5 RE相颗粒数量的增加降低了所得合金的机械性能。热挤压后，所研究的合金表现出双峰微观结构组成的几个微米的细动态再结晶（DRXed）晶粒和强烈织构当然un-DRXed晶粒。挤压态Mg-11.5Gd-4.5Y-1.5Zn-0.3Zr合金表现出优异的强度和塑性平衡（拉伸屈服强度为371 ± 3.0MPa，延伸率为7.2 ± 0.8%）。合金的强化主要归因于双峰组织、Mg 5 RE和LPSO相以及基体织构。经T5处理的Mg-11.5Gd-4.5Y-1.5Zn-0.3Zr合金经沉淀硬化后，其拉伸屈服强度可进一步提高到425 ± 2.5MPa。
The microstructure evolution and mechanical properties of as-extruded Mg-11.5Gd-4.5Y-0.3Zr (wt%) alloy with Zn and Nd additions were investigated. The addition of Zn inhibits the dynamic recrystallization (DRX) due to the presence of the long-period stacking ordered (LPSO) phase. The addition of Nd promotes the precipitation of the Mg5RE (RE: rare earth) phase. The existence of the densely distributed Mg5RE phase before hot extrusion promotes the DRX in subsequent hot extrusion process and leads to grain refinement. The increase in the number of Mg5RE phase particles degrades the mechanical properties of the resultant alloy. After hot extrusion, the studied alloys exhibit a bimodal microstructure consisting of fine dynamic recrystallized (DRXed) grains of several microns and strongly textured course un-DRXed grains. The as-extruded Mg-11.5Gd-4.5Y-1.5Zn-0.3Zr alloy exhibits an excellent balance of strength and ductility (tensile yield strength of 371 ± 3.0 MPa and elongation of 7.2 ± 0.8%). The alloy strengthening is attributed to the bimodal microstructure, the Mg5RE and LPSO phases, and the basal texture. The tensile yield strength of the as-extruded Mg-11.5Gd-4.5Y-1.5Zn-0.3Zr alloy can be further increased to 425 ± 2.5 MPa by precipitation hardening with the T5 treatment.