(南京理工大學(xué) 材料科學(xué)與工程學(xué)院，南京 210094)
摘 要: 針對(duì)高強(qiáng)鋁鎂合金增材構(gòu)件性能難以提升的問題，探索研究了提高鋁鎂合金中的鎂組分這一方法的可行性。基于鎢極氬弧增材制造工藝，采用以ER5356為主要熔化絲材、以少量AZ31為輔助熔化絲材的雙絲同步熔化方式，通過調(diào)整兩種絲材的送絲速度比例，增材制造了5組高鎂組分的鋁鎂合金直壁體，并對(duì)這5組直壁體的顯微組織特征、演化規(guī)律和力學(xué)性能進(jìn)行研究。結(jié)果表明：隨著AZ31與ER5356送絲速度比從1:10提升到1:3，α(Al)相由等軸晶轉(zhuǎn)變?yōu)橹В?Al3Mg2相轉(zhuǎn)變?yōu)榫чg偏析型離異共晶；試樣的平均晶粒尺寸由17.26 μm先增大到21.35 μm再減小到14.69 μm；β相和共晶組織的含量呈上升趨勢(shì)。相較于單絲鋁鎂合金增材構(gòu)件，高鎂組分增材構(gòu)件的平均顯微維氏硬度達(dá)到114.93 HV，提升了64.2%；抗拉強(qiáng)度達(dá)到342 MPa，提升了24.8%。
關(guān)鍵字: 雙絲增材制造；高強(qiáng)鋁鎂合金；顯微組織；力學(xué)性能
（School of Material Science and Engineering, Nanjing University of Science &Technology, Nanjing 210094, China）
Abstract:As the properties of the high strength Al-Mg alloy component is difficult to be improved, a new gas tungsten arc additive manufacturing process was proposed to increase the Mg content in Al-Mg alloy component. Two heterogeneous wires were synchronously fed into the same molten pool, using ER5356 as the main melting wire, and a small amount of AZ31 as the auxiliary melting wire. Five groups of thin wall components with high Mg content were deposited by adjusting the ratio of the feed speed of the two wires. The microstructural characteristics, evolution and mechanical properties of the components were investigated. The results show that with the wire feed speed ratio between AZ31 and ER5356 increasing from 1:10 to 1:3, the α(Al) phase transforms from equiaxed grains to dendrites, and the β-Al3Mg2 phase transforms into divorced eutectics. The average grain size increases from 17.26 μm to 21.35 μm and then decreases to 14.69 μm, meanwhile, the content of the β phase and the eutectic structure increases. Compared with the Al-Mg alloy component deposited by traditional single wire feed gas tungsten arc additive manufacturing process, the micro Vickers hardness of the high Mg content components reaches 114.93 HV on an average, increased by 64.2% and the ultimate tensile strength reaches 342 MPa, increased by 24.8%.
Key words: double wires additive manufacturing; high strength Al-Mg alloy; microstructure; mechanical properties
