中熵合金粉末对铝/钢熔钎焊接头组织性能影响  

Influence of medium entropy alloy powder on microstructure and properties of aluminum/steel brazing joints

作　　者：吴玮[1] 殷相杰 蒋启明 李坤航 杨宏睿 邓展鹰 黄宏 WU Wei;YIN Xiangjie;JIANG Qiming;LI Kunhang;YANG Hongrui;DENG Zhanying;HUANG Hong(College of Materials Science and Engineering,Chongqing University of Technology,Chongqing 400054,China)

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054

出　　处：《重庆理工大学学报（自然科学）》2023年第3期147-154,共8页Journal of Chongqing University of Technology：Natural Science

基　　金：重庆市自然科学基金项目(cstc2021jcyj-msxmx0391);重庆理工大学研究生科研创新项目(clgycx 20202010、gzlcx20223013、gzlcx20223019、gzlcx20222007)。

摘　　要：采用涂敷和预制2种方式加入CoCrNi中熵粉末,研究该合金化粉末对铝/钢TIG熔钎焊接头形貌和组织性能的影响。试验结果表明:钢侧坡口涂敷中熵合金粉时,钎接面有椭球状未熔CoCrNi颗粒层存在,颗粒周围缝隙由灰色的Al基体和Al 0.7 Si 3Fe 0.3填充,界面两侧Al、Fe无明显元素扩散,残余CoCrNi颗粒一定程度上起到了增强相作用,但是其大小和分布的不均匀性影响了液态AlSi_(5)焊丝的流动,背面焊缝包覆性差,形成了较高余高和底部未熔合缺陷。预制方式下CoCrNi粉熔化与钢界面结合良好,熔敷金属在铝和钢表面有较好铺展,接头成形好,界面两侧各元素发生相互扩散,界面生成了Al_(0.7)Si_(3)Fe_(0.3)、Co_(3)Fe_(7)、Fe(Cr,Ni)和Al_(0.9)Ni_(1.1),金属间化合物(IMC)层平均厚3.15μm。CoCrNi中熵粉末有效阻隔了Al-Fe金属间化合物生成,2种方式下接头强度均大于未添加中熵合金粉的接头,其中预制中熵合金粉的强度较高(86 MPa)。涂敷中熵合金粉的接头维氏硬度最高达到467HV,位于钎接界面近焊缝侧,预制中熵合金粉的钢侧出现软化区,接头维氏硬度最高为248HV,位于近钎接界面钢侧。This paper investigates the effects of medium entropy powder CoCrNi on the morphology and microstructure properties of aluminum/steel TIG brazing joints by coating and prefabrication.The results show that,when the side groove of the steel is coated with medium entropy alloy powder,there is an ellipsoidal unmelted CoCrNi particle layer that can be observed on the brazing surface.The gaps around the particles are filled with gray Al matrix and Al_(0.7)Si_(3)Fe_(0.3),and there is no obvious elemental diffusion of Al and Fe.The residual CoCrNi particles play a role of enhancing the phase to a certain extent,but the inhomogeneity of their size and distribution affects the flow of the liquid AlSi 5 welding wire,which leads to poor coverage of the back welding seam,with high weld reinforcement and unfused defects.Under the prefabricated condition,the CoCrNi powder melts and bonds well with the steel interface.Moreover,the fused metal spreads well on both aluminum and steel surfaces,and joints form well.With the interdiffusion of elements,an intermetallic compound(IMC)layer composed of Al_(0.7)Si_(3)Fe_(0.3)、Co_(3)Fe_(7)、Fe(Cr,Ni)and Al_(0.9)Ni_(1.1) forms at the interface,with an average thickness of 3.15μm.CoCrNi powder significantly reduces the formation of brittle IMC such as Fe-Al phases.Therefore,the tensile strength of the two methods is greater than that of the joint without adding medium entropy alloy powder,and the strength of the prefabricated medium entropy alloy powder is as high as 86 MPa.The maximum Vickers hardness of the joint coated with medium entropy alloy powder reaches 467HV,which is located on the side of the brazing interface near the weld.However,there is a softening zone on the steel side of the CoCrNi under the prefabrication mode,and the highest hardness Vickers is located on the steel side near the brazing interface,which is up to 248 HV.

关 键 词：CoCrNi中熵粉末 铝/钢 TIG熔钎焊 形貌 组织性能 

分 类 号：TG444.74[金属学及工艺—焊接] TG457