Al-Mg-Si合金电弧熔丝增材构件组织与性能

Microstructure and Tensile Properties of Double–Wire+Arc Additive Manufactured Al–Mg–Si Alloy

以复合超高频脉冲方波变极性钨极氩弧(HPVP–GTAW)为热源,Al–5Mg(ER5087)和Al–5Si(ER4043两种焊丝为填丝材料进行铝合金电弧熔丝增材制造,通过控制两焊丝的送丝速度获得不同主要合金元素Mg和Si含量的Al–Mg–Si合金薄壁构件,试验研究不同Mg/Si比及热处理对薄壁构件组织及性能的影响。结果表明:合金组织主要由柱状晶及少量等轴晶组成,呈非均匀分布。调节主要合金元素含量可实现对铝合金增材构件性能的控制,随着Mg/Si比的增加,增材构件的力学性能呈上升趋势,各向同性;经过固溶及人工时效热处理后,增材构件的力学性能得到显著提升,但塑性降低。

Double–wires+arc additive manufacturing (D–WAAM) system for Al–Mg–Si alloy using hybrid pulsedvariable polarity gas tungsten arc welding (HPVP–GTAW) process was established. When two different alloying wires (Al– 5Mg + Al–5Si) were used, ternary (Al–Mg–Si) alloys with various compositions can be obtained by adjusting the wire feed speed of the two wires. Mechanical properties of the as-deposited and heat treatment Al–Mg–Si alloys were investigated. Microstructures of Al–Mg–Si deposits are mainly composed of columnar and equiaxed dendrite grains with non-uniform distribution characteristics. Mechanical properties of the as-deposited and heat treatment Al–Mg–Si alloys were investigated. Experimental results show that with the increase of the Mg/Si ratio, tensile properties of the as-deposited alloy increased, which were also nearly isotropic along the two directions. After heat treatment, tensile property of some specimens increased a lot but too much plasticity was loosed.