摘要
针对铝基复合材料高效率、低成本增材制造,提出了铝合金熔滴复合电弧沉积同步颗粒强化增材制造新方法。实验研究中,以倾斜变极性电弧为热源,2024铝合金为基体材料,球形WC颗粒为增强相。成形过程中,由熔滴发生系统产生的铝合金熔滴,竖直落入倾斜电弧产生的熔池,与此同时WC颗粒以气载粉的方式送入熔池后沿,并随着电弧和基板的相对运动分散在铝合金基体中。单道多层沉积实验结果表明,送粉位姿、载气流量和WC颗粒直径均对WC;/Al沉积过程影响显著。保持送粉方向平行于钨针轴线,且粉末流汇聚于熔池后沿时,有利于在沉积过程中保持电弧形态的稳定并获得较高的颗粒植入比例。金相分析显示,WC;/Al沉积层内WC颗粒分布总体均匀,且颗粒与基体结合可靠;WC颗粒的存在会抑制柱状晶的生长,并且当WC颗粒直径小于40μm时,具有显著的晶粒细化效果。
A novel droplet + arc deposition additive manufacturing with ceramic particle simultaneous reinforcement has been proposed for the high-efficiency and low-cost fabrication of aluminum matrix composites. In the experimental study, the tilted variable polarity arc was used as heat source, Al2024 was used as the matrix and spherical WC particles were used as reinforcement phases. During the AM process, the droplets which generated from an independent generator fall vertically into the molten pool and the WC particles are feeding into the back edge of the molten pool simultaneously. The WC particles will disperse into the aluminum matrix with the relative motion of the arc and the substrate. The results show that the WC feeding direction, the flow rate of the carrier gas and the size of WC particle all have significant effects on the AM process. When the powder feeding direction is parallel to the axis of the tungsten needle, and the powder streams converge at the back edge of the molten pool, it is beneficial to maintain the stability of arc and obtain a high proportion of WC implantation. The metallographic analysis shows that the distribution of WC particles is generally uniform and the combination between WC particle and Al2024 matrix is reliable. The existence of WC will inhibit the growth of columnar crystals, and the grain size of matrix can be refined significantly when the WC size is less than 40 μm.
作者
贺鹏飞
魏正英
杜军
蒋敏博
马琛
HE Peng-fei;WEI Zheng-ying;DU Jun;JIANG Min-bo;MA Chen(The State Key Laboratory for Manufacturing Systems Engineering,Xi'an Jiaotong University,Xi'an 710049)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第5期258-267,共10页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(51775420)。
