【摘要】 粉末锻造技术将传统的压制烧结粉末冶金技术与精密闭式热模锻技术的优点相结合，对烧结的预压件在闭式模具中进行一次锻打即可产出力学性能优良的近净成形产品。以Al-Mg-Si系6061铝合金为模型材料研究合金的粉末锻造工艺及力学性能，对烧结6061铝合金进行热模拟分析，得到其本构方程和热加工图，之后通过闭式热模锻制备了粉末锻造6061铝合金，并对比研究了锻造态合金与烧结态合金T6热处理前后微观组织与力学性能。结果表明，烧结6061铝合金热加工性能较好，在425～500℃/0.01～1 s^-1范围内变形时无失稳现象。相较于烧结态合金，锻造态合金平均晶粒尺寸由12.3μm变为9.6μm，合金元素分布更加均匀，致密度由96.68%提升至99.71%，硬度由40.9HV提升至64.7HV，屈服强度提高75%，可达129 MPa，抗拉强度提高58%，可达220 MPa，断后伸长率提高138%，可达29.6%；经过T6热处理之后，锻造态合金的主要强化相主要为β"相和β相，其硬度、屈服强度、抗拉强度和伸长率分别为135.2HV、301 MPa、372 MPa和12.0%。更多还原

【Abstract】 As an economic technology with the advantages of powder metallurgy and precision hot die forging, powder forging is a near-net-shape manufacturing technology, which produces parts with high precision and excellent mechanical properties by forging the preformed sintered compact. In this study, we provide a strategy to study the powder forging process as well as the mechanical properties of aluminum alloys using 6061 as an example. The constitutive equations and thermal processing maps of the sintered 6061 aluminum alloy are established through the thermal simulation, and on the basis of thermal analyses, the 6061 aluminum alloy is fabricated via powder metallurgy followed by precision hot die forging. Investigation on the microstructure and mechanical properties of assintered and as-forged aluminum alloys before and after T6 heat treatment are also carried out. The results show that the sintered 6061 aluminum alloy without instability during deformation in the range of 425-500 ℃/0.01-1 s^-1, indicating its excellent hot workability. Compared with the as-sintered alloys, the average grain size of as-forged alloys decreased from 12.3 μm to 9.6 μm, which enabled a uniform distribution of alloying elements. As a result, the density, hardness, yield strength and tensile strength reach 99.71%, HV64.7, 129 MPa and 220 MPa, respectively. In particular, it is noted that the as-forged alloy experienced a 138% increase in its elongation, achieving 29.6%. After T6 heat treatment, the as-forged alloys exhibit a hardness of HV135.2, a yield strength of 301 MPa, a tensile strength of 308 MPa and an elongation of 12%, and the dominant strengthening phases are composed of β" and β phases.更多还原