The effect of arc characteristic on microstructure and properties of 5A56 Al alloy in CMT arc additive manufacturing

CMT电弧特性对5A56铝合金增材制造构件组织与性能的影响 The effect of arc characteristic on microstructure and properties of 5A56 Al alloy in CMT arc additive manufacturing 王会霞 WANG Huixia 1 2 3 first-author 王松涛 WANG Songtao 1 王天顺 WANG Tianshun 1 张亮 ZHANG Liang 1 2 3 河北科技大学材料科学与工程学院 河北科技大学材料科学与工程学院 School of Materials Science and Engineering,Hebei University of Science and Technology School of Materials Science and Engineering,Hebei University of Science and Technology 河北省材料近净成形技术重点试验室河北科技大学 河北省材料近净成形技术重点试验室河北科技大学 Hebei Key Laboratory of Material Near-Net Forming Technology,Hebei University of Science and Technology Hebei Key Laboratory of Material Near-Net Forming Technology,Hebei University of Science and Technology 河北省航空轻质复合材料与加工技术工程试验室河北科技大学 河北省航空轻质复合材料与加工技术工程试验室河北科技大学 为了研究CMT电弧特性对铝合金增材制造构件组织与性能的影响,采用CMT、CMT-VP及CMT-P三种电弧形式分别对5A56铝合金进行电弧增材制造。通过高速摄像同步采集系统分析增材制造中的电弧形态及熔滴过渡过程进行跟踪,研究电弧特性对铝合金增材制造构件微观组织与力学性能的影响。试验结果表明:电弧特性对电弧行为和熔滴过渡都产生影响,CMT-VP电弧的EN阶段电弧形态发生变化,弧根上爬包裹熔滴,极区热量使焊丝熔化量增加;CMT-P中脉冲阶段电弧电压和电流都处于峰值且电流峰值较高,导致电弧力较大,熔滴过渡呈滴状,熔池振荡;在焊接电流与熔敷速度相同情况下电弧的线能量大小为CMT-P>CMT>CMT-VP,较低的热输入量使得CMT-VP电弧下薄壁试样的晶粒尺寸最小,组织分布较为均匀,且CMT-VP电弧下试样的力学性能更为优异,硬度均值最高,达到86.01 HV,横向与纵向抗拉强度均最大,分别为344.68 MPa和324.61 MPa,其延伸率分别为30.33%和21.04%。而CMT-P电弧的热输入最大,易形成粗晶组织,力学性能较差。 In order to investigate the effect of CMT arc characteristics on the microstructure and properties of alumi-num alloy additive manufacturing components,5A56 aluminum alloy was fabricated by arc additive manufacturing with three mode of CMT,CMT-VP and CMT-P respectively. The arc behavior and metal transfer during additive manufacturing were observed by high-speed camera and data acquisition system,the effect of arc characteristics on the microstructure and mechanical properties of aluminum alloy additive manufac-turing specimen was studied. The experimental results show that the CMT arc characteristics has an impact on the arc behavior and metal transfer,the arc behavior is changed in the period of electrode negative in CMT-VP arc,the negative polarity climbs to the wire and wraps the droplet,the heat of melting wire is increased accordingly. In the pulse period of CMT-P,the voltage and current are both in peak and the current peak value is high,resulting in large arc force,the metal transfer in droplet mode and molten pool oscillation. When the welding current and deposition speed are the same,the heat input of the arc is CMT-P>CMT>CMT-VP. The grain size of the deposited metal with lower linear energy of CMT-VP arc is the smallest and the microstructure distribution is more uniform,the deposited metal shows more excellent mechanical properties and the average hardness is the highest,reaching 86.01 HV,and the transverse and longitudinal tensile strength are the largest in CMT-VP,which is 344.68 MPa and 324.61 MPa respectively,and the elongation get to 30.33% and 21.04% respectively. CMT-P has the largest heat input,which can get to form coarse-grained structure and poor mechanical properties. 电弧增材制造 电弧特性 微观组织 力学性能 wire arc additive manufacturing arc characteristic microstructure mechanical property TG146.21 河北省高等学校科学技术研究项目（ZD2018060）;河北省自然科学基金（E201908199）;空军工程大学等离子体国防重点实验室基金（61422030602） 2022-03-08 8 51