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通过铸锻复合工艺加工ADC12铝合金,该工艺包括间接挤压铸造和锻造,分别对重力铸造态、挤压铸造态和铸锻复合态的ADC12铝合金的力学性能和显微组织进行了研究。结果表明,挤压铸造的ADC12铝合金具有更细的Al-Si共晶组织,针状共晶组织减少,其平均晶粒尺寸为37.25μm,较重力铸造态降低了36.51%,其抗拉强度和伸长率分别为240MPa和1%,较重力铸造的分别提高了34.08%和14.9%;铸锻复合后,组织进一步细化,Al-Si共晶组织被压碎,其平均晶粒尺寸为26.54μm,较重力铸造降低了28.75%,其抗拉强度和伸长率分别达到287.75 MPa和4.4%,较挤压铸造态分别提高了19.8%和340%。从拉伸断口形貌上可发现,铸态断口为典型的脆性断口,挤压铸造和铸锻复合后,都属准解理断裂,但是铸锻复合后,韧窝更浅而小,解理面和撕裂棱变得细小,断裂单元变小,韧性断裂趋势增加。经分析,晶粒细化及Al-Si共晶组织分布状态的改变是ADC12合金抗拉强度和伸长率提高的主要因素。
The ADC12 aluminum alloy was machined by a combination of casting and forging process, which includes indirect extrusion casting and forging. The mechanical properties and microstructure of ADC12 aluminum alloy were investigated respectively in gravity casting, squeeze casting and casting / wrought composite states. The results show that the die-cast ADC12 aluminum alloy has finer Al-Si eutectic microstructure, reduced needle-shaped eutectic structure, an average grain size of 37.25μm and a decrease of 36.51% And elongation were 240MPa and 1%, respectively, compared with gravity casting increased 34.08% and 14.9%; after casting and forging composite, the organization further refinement, Al-Si eutectic is crushed, the average grain size of 26.54 μm, which is 28.75% lower than that of gravity casting. The tensile strength and elongation reach 287.75 MPa and 4.4% respectively, which are respectively 19.8% and 340% higher than that of extrusion casting. From the appearance of the tensile fracture, it can be found that the as-cast fracture is a typical brittle fracture, which is a quasi-cleavage fracture after squeeze casting and cast-forging. However, after dipping and forging, the dimples are shallower and smaller, cleavage Surfaces and tearing edges become smaller, fracture units become smaller, and tenacity fracture tendency increases. The analysis shows that the grain refinement and Al-Si eutectic microstructure changes are the main factors for improving the tensile strength and elongation of the alloy.