CAJ | 학술논문

采用粉末热挤压法制备了一种Al-Zn-Mg-Cu超高强铝合金,研究了粉末粒度和挤压比对合金组织和力学性能的影响.结果表明,400℃挤压时,粉末中位径D_(50)=28.38μm和挤压比λ=25可使挤压合金获得最好的力学性能,挤压合金经过460℃/2.5h水淬+120℃/24h空冷(T6)处理后的抗拉强度、屈服强度和伸长率分别为731MPa,670MPa和6.2%;晶粒细化是挤压合金力学性能随粉末粒度减小而提高的原因;挤压比λ为9～25时,挤压合金力学性能随挤压比增大而提高;λ=36时,挤压合金力学性能降低的原因是MgZn_2析出相粗大和发生完全动态再结晶.
채용분말열제압법제비료일충Al-Zn-Mg-Cu초고강려합금,연구료분말립도화제압비대합금조직화역학성능적영향.결과표명,400℃제압시,분말중위경D_(50)=28.38μm화제압비λ=25가사제압합금획득최호적역학성능,제압합금경과460℃/2.5h수쉬+120℃/24h공랭(T6)처리후적항랍강도、굴복강도화신장솔분별위731MPa,670MPa화6.2%;정립세화시제압합금역학성능수분말립도감소이제고적원인;제압비λ위9～25시,제압합금역학성능수제압비증대이제고;λ=36시,제압합금역학성능강저적원인시MgZn_2석출상조대화발생완전동태재결정.
In this study, an Al-Zn-Mg-Cu ultra strength aluminium alloy was fabricated by powder hot extrusion process, and the effects of powder granularity and extrusion ratio on microstructures and mechanical properties of alloys were investigated. The results show that the optimal powder median size (D_(50)) for the consolidation of alloyed powder is 28.38μm, and the extrusion ratio (λ) is 25. By extrusion at 400℃, the best mechanical properties were obtained with the above as-optimized processing parameters. After T6 temper, i.e. 460℃×2.5h water quenching +120℃×24h air cooling, the tensile strength, yield strength and elongation of the heat treated alloy are 731MPa, 670MPa and 6.2%, respectively. The mechanical properties of extruded alloys increasing with the decrease of powder granularity are due to grain refinement. The mechanical properties of extruded alloys increase with the increase of extrusion ratio from 9 to 25. Coarse MgZn_2 precipitated phases and complete dynamic recrystallization lead to the reducing of mechanical properties of the extruded alloy produced by extrusion ratio 36.