钇含量对电弧增材制造2319铝合金组织与性能的影响

以不同钇含量的2319铝合金丝材为原材料，采用基于冷金属过渡的电弧增材制造工艺(wire arc addictive manufacturing，WAAM)制备2319铝合金，研究了钇含量对WAAM 2139铝合金的显微组织及力学性能的影响. 结果表明，添加Y元素可明显细化直接沉积态WAAM 2319铝合金的晶粒，细晶强化及第二相强化作用显著，间接影响了时效过程析出的二次析出相θ′的数量，同时，未对直接沉积态WAAM 2319铝合金中气孔缺陷的大小、分布产生显著影响. 随着钇含量的增加，合金凝固过程含钇化合物在晶粒交汇处偏析程度增大，使得合金成分过冷度减小，导致WAAM 2319铝合金的晶粒尺寸呈现先减小后增大的趋势，抗拉强度和屈服强度呈现出先上升后下降趋势，断后伸长率逐渐下降. 当钇含量为0.15%时，WAAM 2319铝合金表现出最优的力学性能，即抗拉强度484 MPa、屈服强度348 MPa和断后伸长率10.5%.

Effect of yttrium content on microstructure and properties of 2319 aluminum alloy fabricated by wire arc additive manufacturing

The wire arc additive manufacturing technology (WAAM) based on cold metal transfer was used to prepare WAAM 2319 aluminum alloys by 2319 aluminum alloy wires with different yttrium (Y) content, and the effect of Y content on the microstructure and mechanical properties of WAAM 2139 alloy were investigated. The results show that the grain of as-deposited WAAM 2319 aluminum alloy is obviously refined after adding Y, which has the effects of fine grain strengthening and second phase strengthening, which affected the formation amount of the secondary precipitates θ' in the aging process indirectly. Meanwhile, the size and distribution of pore defects in WAAM 2319 aluminum alloy are not significantly affected with the addition of Y. With the increase of Y content, the degree of segregation of Y-containing compounds at the grain intersection during the solidification process of the alloy increases, which reduces the component undercooling, and resulting in the grain size of WAAM 2319 aluminum alloy decreases and then increases, the tensile strength and yield strength increase and then decrease, and the elongation decreases gradually. When the Y content reaches 0.15%, WAAM 2319 aluminum alloy reaches the optimal value of mechanical properties with tensile strength of 484 MPa, yield strength of 348 MPa and elongation of 10.5%.