Tuning texture and precipitation using Y/Gd atomic ratio in iso- concentration Mg-Y-Gd-Ag-Zr extruded alloys
Tuning texture and precipitation using Y/Gd atomic ratio in iso- concentration Mg-Y-Gd-Ag-Zr extruded alloys
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使用等浓度 Mg-Y-Gd-Ag-Zr 挤压合金中 Y/Gd 原子比调节织构和析出
DOI：
10.1016/j.matchar.2020.110473
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发表时间：
2020
影响因子：
4.7
通讯作者：
Peng Liming
中科院分区：
文献类型：
--
作者：
Zhang Yu;Rong Wei;Wu Yujuan;Peng Liming
本文研究了三种合金元素总量相同但Y/Gd原子比不同的Mg-Y（-Gd）-Ag-Zr合金在350° C热挤压变形后的显微组织和力学性能。挤压Mg-2.4 Y-0.4 Ag-0.1 Zr（at.%）基体合金呈现出由细小的等轴再结晶晶粒和粗大的细长未再结晶晶粒组成的双峰晶粒组织，并具有01 1 0//艾德（挤压方向）织构。相比之下，当用Gd部分替代Y时，挤压Mg-1.6 Y-0.8 Gd-0.4 Ag-0.1 Zr（at.%）和Mg-0.8 Y-1.6 Gd-0.4 Ag-0.1 Zr（at.%）Y/Gd原子比分别为2和0.5的合金显示出接近完全再结晶的结构，并具有[0001]//艾德织构。Mg-2.4 Y-0.4 Ag-0.1 Zr合金中γ ″相占主导地位，β′相较少，而Mg-1.6 Y-0.8 Gd-0.4 Ag-0.1 Zr和Mg-0.8 Y-1.6 Gd-0.4 Ag-0.1 Zr合金中β′相和γ ″相的数量密度较大。含Gd合金中的沉淀通过用Gd部分取代Y而显著增强。Mg-1.6 Y-0.8 Gd-0.4 Ag-0.1 Zr合金峰时效后，晶界强化、弥散强化和沉淀硬化之间保持了较好的平衡，获得了较好的强度和塑性配合，室温拉伸屈服强度、极限抗拉强度和伸长率分别为377 MPa、479 MPa和8.0%。
Abstract Three Mg–Y (–Gd)–Ag–Zr alloys with an iso-concentration of total alloying elements but different Y/Gd atomic ratios were hot extruded at 350° C and their microstructures and mechanical properties were comparatively studied. Extruded Mg–2.4 Y–0.4 Ag–0.1 Zr (at.%) base alloy shows a bimodal-grained structure composed of fine equiaxed recrystallised grains and coarse elongated unrecrystallised grains and has a 01 1¯ 0//ED (extrusion direction) texture. In contrast, when Y is partially replaced with Gd, extruded Mg–1.6 Y–0.8 Gd–0.4 Ag–0.1 Zr (at.%) and Mg–0.8 Y–1.6 Gd–0.4 Ag–0.1 Zr (at.%) alloys with the Y/Gd atomic ratio of 2 and 0.5, respectively, exhibit a near fully recrystallised structure and have a [0001]//ED texture. While basal γ ″precipitates dominate but few β′ precipitates form in Mg–2.4 Y–0.4 Ag–0.1 Zr alloy, a large number density of both β′ and γ ″precipitates form in Mg–1.6 Y–0.8 Gd–0.4 Ag–0.1 Zr and Mg–0.8 Y–1.6 Gd–0.4 Ag–0.1 Zr alloys after post-extrusion ageing. Precipitation in the Gd-containing alloys is considerably enhanced by partial substituting Y with Gd. The peak-aged Mg–1.6 Y–0.8 Gd–0.4 Ag–0.1 Zr alloy keeps a relatively good balance between grain boundary strengthening, dispersion strengthening and precipitation hardening and thus obtains a good combination of strength and ductility, whose room temperature tensile yield strength, ultimate tensile strength and elongation are 377 MPa, 479 MPa and 8.0%, respectively.