BC-MIG丝材电弧增材制造NAB/钢复合结构的微观组织与力学性能  

Microstructure and mechanical properties of NAB/steel composite structures by additive manufacturing with BCMIG wire arc

作　　者：苗玉刚 刘吉 李小旭 赵羽杨 王子然 张本顺 MIAO Yugang;LIU Ji;LI Xiaoxu;ZHAO Yuyang;WANG Ziran;ZHANG Benshun(Harbin Engineering University,Harbin,150001,China;China Institute of Ship and Ocean Engineering Design,Shanghai,200011,China;Jiangsu Automation Research Institute,Lianyungang,222006,China)

机构地区：[1]哈尔滨工程大学,哈尔滨150001 [2]中国船舶及海洋工程设计研究院,上海200011 [3]江苏自动化研究所,连云港222006

出　　处：《焊接学报》2023年第7期56-62,I0006,共8页Transactions of The China Welding Institution

基　　金：国家自然科学基金面上资助项目(51975138);工信部高技术船舶资助项目(CJ05N20);工信部高技术船舶资助项目(MC-201917-C09)。

摘　　要：使用旁路分流熔化极惰性气体保护焊(bypass current metal inert gas welding,BC-MIG焊)在水冷条件下增材制造镍铝青铜(nickel aluminum bronze,NAB)和25号钢复合结构,以评估异种金属增材制造的可行性.通过光学显微镜、扫描电子显微镜、万能试验机和硬度测试仪研究了热处理前后复合结构的微观组织和力学性能的影响.通过X射线衍射仪研究了界面附近残余应力,结果表明,在BC-MIG焊的低热输入和水冷的高冷却速率下,结构件表面成形良好且自由变形较小,接头未发现缺陷和裂纹.热处理促进了Cu,Fe元素的相互扩散,扩散层由4μm提高到了17μm,但界面没有形成Fe-Al金属间化合物层.在水冷条件下,钢的残余应力分布在−350~−250 MPa之间,而NAB的残余应力差异较大,在−550~90 MPa之间.拉伸试验结果表明,热处理后,由于残余应力降低,结构的抗拉强度略微降低,但断后伸长率明显提高.创新点:(1)将BC-MIG焊和水冷结合用于NAB/钢增材制造,有效控制了焊接热输入,解决了NAB/钢界面渗透裂纹和脆性金属间化合物问题.(2)采用适当的焊后热处理提高了韧性并降低了残余应力,阐明了残余应力降低的机理.Nickel-aluminum bronze(NAB)and grade 25 steel composite structures were fabricated using bypass current metal inert gas(BC-MIG)welding arc additive manufacturing technology under water-cooled conditions to evaluate the feasibility of dissimilar metal additive manufacturing.The results showed that under low heat input of BC-MIG welding and high water cooling rate,the surface of the additive manufacturing structure was well-formed with minimal deformation and no defects or cracks were found in the joints.The influence of heat treatment on the microstructure and mechanical properties was studied.Heat treatment promoted the mutual diffusion of Cu and Fe elements,and the diffusion layer increased from 4μm to 17μm,and no Fe-Al intermetallic compound layer was formed at the interface.Residual stresses near the interface were studied by X-ray diffractometer.The results showed that under water-cooling conditions,the residual stresses of steel were distributed among−350 MPa to−250 MPa,while the residual stresses of NAB varied significantly from−550 MPa to 90 MPa.Tensile test results showed that after heat treatment,the tensile strength of the structure decreased slightly due to the reduction of residual stress,but the elongation was significantly improved.Highlights:(1)The combination of BC-MIG welding and water cooling was used for NAB/steel additive manufacturing,which effectively controlled the welding heat input and solved the problems of penetration cracks and brittle intermetallic compounds at the NAB/steel interface.(2)Adoption of appropriate post-weld heat treatment improves toughness and reduces residual stress,and elucidates the mechanism of residual stress reduction.

关 键 词：旁路分流 镍铝青铜 钢 丝材电弧增材制造 热处理 

分 类 号：TG457[金属学及工艺—焊接]