变形温度对2A14铝合金组织与力学性能的影响

Effects of Deformation Temperature on Microstructure and Mechanical Properties of 2A14 Aluminum Alloy

针对大型2A14铝合金高筒件制造存在的粗大晶粒与第二相聚集等问题,本研究提出一种高筒件中温轧制新工艺。借助金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)与拉伸测试等手段研究了热轧与中温轧制对2A14铝合金组织与力学性能的影响。结果表明:相较于480℃热轧,2A14铝合金在200℃下进行中温轧制并结合热处理可显著提升其综合力学性能,其抗拉强度、屈服强度、延伸率分别达到464 MPa、386 MPa、9.3%。中温轧制以高密度位错形式累积大量存储能,提高了固溶过程的再结晶形核率,使晶粒显著细化;同时,中温轧制协同热处理使合金中粗大第二相化合物充分破碎与溶解,改善了其在基体中的不均匀分布,并促进了2A14铝合金主要强化相S′相的析出。

Aiming at the problems of coarse grains and second phase aggregation in the manufacture of large 2A14 aluminium alloy high cylinder parts,a new warm rolling process for high cylinder parts was proposed in this paper.The effects of hot and warm rolling on the microstructure and mechanical properties of 2A14 aluminum alloy were studied by using optical microscope(OM),scanning electronic microscopy(SEM),transmission electron microscopy(TEM)and tensile test.The results show that the comprehensive mechanical properties of 2A14 aluminium alloy can be significantly improved by warm rolling at 200℃combined with heat treatment compared with that of hot rolling at 480℃.The tensile strength,yield strength and elongation of 2A14 aluminum alloy can reach 464 MPa,386 MPa and 9.3%,respectively.A large amount of storage energy accumulated in the form of high density dislocation during warm rolling promotes the nucleation rate of recrystallization during solution process and refines dramaticly grain size.Meanwhile,warm rolling combined with heat treatment can fully break up and dissolve the coarse second-phase compounds in the alloy,improve their non-uniform distribution in the matrix,and promote the precipitation of S′phase,the main strengthening phase of 2A14 aluminum alloy.