摘要
A new Mg-6 Er-3 Y-1.5 Zn-0.4 Mn(wt.%) alloy with high strength at high temperature was designed and extruded at 350℃. The as-extruded alloy exhibits ultimate tensile strength of 301 MPa, yield strength(along ED) of 274 MPa and thermal conductivity of 73 W/m·K at 300℃. Such outstanding hightemperature strength is mainly attributed to the formation of nano-spaced solute-segregated basal plane stacking faults(SFs) with a large aspect ratio throughout the entire Mg matrix, fine dynamically recrystallized(DRXed) grains of 1–2μm and strongly textured un-DRXed grains with numerous sub-structures.Microstructural examination unveils that long period stacking ordered(LPSO) phases are formed in Mg matrix of the as-cast alloy when rational design of alloy composition was employed, i.e.(Er + Y): Zn = 3:1 and Er: Y = 1: 1(at.%). It is worth mentioning that it is the first report regarding the formation of nano-spaced basal plane SFs throughout both DRXed and un-DRXed grains in as-extruded alloy with well-designed compositions and processing parameters. The results provide new opportunities to the development of deformed Mg alloys with satisfactory mechanical performance for high-temperature services.
A new Mg-6 Er-3 Y-1.5 Zn-0.4 Mn(wt.%) alloy with high strength at high temperature was designed and extruded at 350℃. The as-extruded alloy exhibits ultimate tensile strength of 301 MPa, yield strength(along ED) of 274 MPa and thermal conductivity of 73 W/m·K at 300℃. Such outstanding hightemperature strength is mainly attributed to the formation of nano-spaced solute-segregated basal plane stacking faults(SFs) with a large aspect ratio throughout the entire Mg matrix, fine dynamically recrystallized(DRXed) grains of 1–2μm and strongly textured un-DRXed grains with numerous sub-structures.Microstructural examination unveils that long period stacking ordered(LPSO) phases are formed in Mg matrix of the as-cast alloy when rational design of alloy composition was employed, i.e.(Er + Y): Zn = 3:1 and Er: Y = 1: 1(at.%). It is worth mentioning that it is the first report regarding the formation of nano-spaced basal plane SFs throughout both DRXed and un-DRXed grains in as-extruded alloy with well-designed compositions and processing parameters. The results provide new opportunities to the development of deformed Mg alloys with satisfactory mechanical performance for high-temperature services.
基金
supported by National Natural Science Foundation of China (No. 51871069)
Natural Science Foundation of Heilongjiang Province of China (E2017030)
Fundamental Research Funds for the Central Universities (3072019CF1004)
Foundation of State Key Laboratory of Rare Earth Resources Utilization (No. RERU2018017)
