304LN和Inconel625+10%WC复合增材制造过程中的裂纹控制及组织性能研究  

Crack Inhibition and Optimization of Microstructure and Mechanical Properties in 304LN and Inconel625+10%WC Multiple-material Fabricated by Additive Manufacturing

作　　者：金俊希 温雪龙 王志国[2] 赵宇辉[2] 贺晨 赵吉宾[2] JIN Junxi;WEN Xuelong;WANG Zhiguo;ZHAO Yuhui;HE Chen;ZHAO Jibin(School of Mechanical Engineering and Automation,Northeastern University,Shenyang 110819,China;Shenyang Institute of Automation,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]东北大学机械工程与自动化学院,沈阳110819 [2]中国科学院沈阳自动化研究所,沈阳110016

出　　处：《精密成形工程》2025年第4期192-202,共11页Journal of Netshape Forming Engineering

基　　金：沈阳市中青年科技创新人才支持计划(RC220527);“兴辽英才计划”青年拔尖人才(XLYC2203154);揭榜挂帅项目(2022JH1/10800048);2023年数字辽宁智造强省(智造强省方向)专项资金项目(辽工信投资【2023】171号)。

摘　　要：目的采用激光增材工艺对304LN和Inconel625+10%(质量分数)WC进行整体同步打印,制备无裂纹双金属材料零件,研究裂纹产生原因并测试零件的性能。方法通过优化打印策略以减少乃至避免裂纹产生,利用光学显微镜、电子显微镜(SEM)和能谱仪(EDS)等手段,分析各打印策略对应试件界面处的显微组织、元素过渡等情况,探究裂纹形成机理。采用维氏硬度计、万能材料试验机测试双金属材料零件的硬度及弯曲强度。结果有宏观和微观2种原因可能导致裂纹的产生:宏观上,304LN和Inconel625材料的热膨胀系数不同,熔覆后冷却收缩速度存在差异,当2种材料在同一熔覆层的混合交融程度较高时,这种收缩速度的差异会使熔覆层拉伸并产生较大热应力,从而导致裂纹产生;微观上,Nb、Mo等固溶体强化元素的偏析导致碳化物等次生相在晶界处聚集形成低熔点共晶相,降低了晶界的结合强度,削弱了固溶体强化效应,使力学性能减弱,裂纹敏感性提高,这些低熔点共晶相在后续层的加热中液化成液膜,然后被残余应力拉开。无裂纹双金属材料零件的弯曲强度为1300 MPa左右,304LN区域硬度约为180HV,Inconel625/WC区域硬度约为350HV。结论通过优化打印策略,采用从下至上依次熔覆材料的方式,可以降低熔化的Inconel625+10%WC材料对304LN熔覆区域的稀释作用,实现无裂纹双金属材料的制备。制备的整体梯度结构硬度转变区短,硬度过渡快,并且在弯曲过程中,在界面位置未发现裂纹,且整体性能优于单一304LN结构的性能。The work aims to prepare crack-free bimetallic parts by integral simultaneous printing of 304LN and Inconel625+10%WC through laser additive process and study the causes of crack generation and test the properties of the parts.The printing strategy was optimized to reduce or even avoid cracks.Optical microscopy,electron microscopy(SEM)and energy spectrometry(EDS)were used to analyze the microstructure and elemental transition at the interface of the specimens produced by each printing strategy,and to investigate the crack formation mechanism.Vickers hardness tester and universal material testing machine were used to test the hardness and bending strength of the bimetallic parts.There were both macro and micro causes that might lead to cracks.Macroscopically,the thermal expansion coefficients of 304LN and Inconel625 materials were different,and there was a difference in the cooling shrinkage rate after melting,and when the two materials were mixed and intermixed to a high degree in the same melting layer,this difference in shrinkage rate stretched the melting layer to produce a large thermal stress,which led to cracks.Microscopically,the segregation of solid solution strengthening elements such as Nb,Mo and other solid solution strengthening elements led to the formation of low melting point eutectic phase by aggregation of carbides and other secondary phases at grain boundaries,resulting in weak grain boundaries,weakened solid solution strengthening,weak mechanical properties,high susceptibility to cracking,and liquefaction into a liquid film during heating of the subsequent layer,which was then stretched apart by the residual stress.The flexural strength of the crack-free bimetallic parts was around 1300 MPa,the hardness in the 304LN region was around 180HV,and the hardness in the Inconel625/WC region was around 350HV.By optimizing the printing strategy and adopting a bottom-to-top sequential melting of the materials,the dilution effect of the melted Inconel625+10%WC material on the 304LN melting region can be co

关 键 词：激光熔覆 304LN/Inconel625 双金属材料 策略优化 裂纹控制 

分 类 号：TG14[一般工业技术—材料科学与工程]