双丝电弧增材梯度材料的工艺性能

Processing properties of gradient material fabricated by double wire arc additive manufacturing

双丝电弧增材技术是一种利用电弧热熔化两种不同种类焊丝的增材制造技术。使用MG70S-6和QD266两种焊丝,通过调节双丝的送丝速度制备沿高度方向呈现不同性能的梯度功能材料,同时研究增材的微观组织,分析梯度材料的力学性能。试验结果表明,通过调节送丝速度可改善增材成形效果;优化后的梯度材料主要由胞状晶和树枝晶组成,且生长方向沿高度方向发生变化,微观组织主要为铁素体和少量珠光体构成,在顶层出现少量的贝氏体组织;随着每层耐磨焊丝熔敷比例增加,淬硬组织增多,硬度值也逐层递增,顶层硬度值达到451.9 HV。

Double wire welding arc additive manufacturing(Double-wire WAAM)technology is a kind of new technology that can fabricate materials by using arc heat to melt two different welding wires.MG70S-6 and QD266 wires were used in the experiment.The gradient materials with different properties in vertical direction were fabricated by adjusting the feeding speed of two wires,and then microstructures and mechanical properties of additive material were analyzed.The result showed that the forming effect could be improved by adjusting the feeding speed of two wires.In addition,microstructures of the optimized additive material mainly consisted of cellular grains and dendritic grains and its growth direction changed along the height direction.The components of the microstructure were ferrite and a small amount of pearlite,and few bainite appeared on top.Finally,with deposition ratio of wear-resisting welding wire layer by layer increasing,more quenched microstructures formed and its hardness values increased layer by layer.The hardness of top layer reached 451.9 HV.