CMT电弧增材制造2319铝合金微观组织与力学性能分析

Microstructure and mechanical properties analysis of CMT arc-additivemanufactured 2319 aluminum alloy

采用CMT(冷金属过渡)技术电弧增材制造了2319铝合金直壁墙,并分别对沉积态和热处理态2319铝合金组织和性能进行分析。沉积态2319铝合金,层内区域为等轴晶组织,层间区域气孔缺陷较多,同时晶粒分布为粗大柱状晶和等轴晶的交混组织,沉积态2319铝合金纵向抗拉强度251 MPa,横向抗拉强度255 MPa。将沉积态2319铝合金进行热处理强化,优化固溶和时效制度,根据硬度确定最佳热处理制度:固溶温度535℃、固溶时间1 h、时效温度175℃和时效时间12 h,经过热处理后的2319铝合金,可引入高密度、细小、针状分布的θ″-Al2Cu相,产生析出强化效应,使得合金抗拉强度达449 MPa,较沉积态提升了76%。

The 2319-aluminum-alloy straight wall was fabricated with arc additive using CMT technology,and the microstructure and mechanical properties of 2319 aluminum alloy in deposited and heat-treated states were analyzed.For the as-deposited 2319 alloy,the intralayer zone is equiaxed crystal structure,and more porosity defects appear in the inter-layered zones.The grain distribution is a mixed one with coarse columnar and equiaxed crystals,with longitudinal tensile strength and transverse tensile strength of 251 MPa and 255 MPa respectively for the as-deposited 2319 aluminum alloy.The as-deposited 2319 aluminum alloy is strengthened by heat treatment,the solution and aging systems are optimized and the best heat-treatment system is determined based on hardness,i.e.solution at 535℃for 1 h and aging at 175℃for 12 h.After that,a high-density,fine and needle-likeθ″-Al 2Cu phase can be introduced into 2319 aluminum alloy,resulting in precipitation strengthening effect,which lifts tensile strength up to 449 MPa,76%higher than that without heat treatment.