基于选区激光熔化镍基单晶高温合金的修复  

Repair of nickel-based single crystal superalloy based on selective laser melting

作　　者：张宇 沈超[1,2] 张鹏 章林 曲选辉[1,2] ZHANG Yu;SHEN Chao;ZHANG Peng;ZHANG Lin;QU Xuanhui(Institute of New Materials Technology,University of Science and Technology Beijing,Beijing 100083,China;Beijing Advanced Innovation Center for Materials Genome Engineering,University of Science and Technology Beijing,Beijing 100083,China;Institute of Materials Intelligent Technology,Liaoning Academy of Materials,Shenyang 110000,China)

机构地区：[1]北京科技大学新材料技术研究院,北京100083 [2]北京科技大学北京材料基因组高精尖创新中心,北京100083 [3]辽宁材料实验室材料智能技术研究所,沈阳110000

出　　处：《中国有色金属学报》2024年第4期1376-1392,共17页The Chinese Journal of Nonferrous Metals

基　　金：国家重点研发计划资助项目(2022YFB3705400);国家自然科学基金资助项目(52074032,51974029,52071013,52130407);北京市自然科学基金资助项目(2232084);广东省基础与应用基础研究基金资助项目(2021B1515120033,BK20BE015);高等学校学科创新引智计划资助项目(111计划)(B170003)。

摘　　要：选区激光熔化技术光斑和热影响区小,成形精度高,可对镍基单晶高温合金叶片进行有效的修复以延长使用寿命。本工作选用了一种具有中等体积分数γ′相的合金粉末,研究了在单晶CM247LC基板上进行外延生长过程中该合金粉末的显微组织演变规律以及力学性能。结果表明:修复界面的熔池宽深比大于4时,沉积区与基体能形成良好的结合界面以及较小的晶粒取向差。通过增大扫描速率和降低激光功率可以有效减小沉积区裂纹密度,沉积组织以沿沉积方向生长的柱状枝晶为主,沉积层越高,冷却速率越小,枝晶间距和晶粒取向差越大。通过打印参数优化,最终得到了裂纹密度低、晶粒取向单一、且与单晶基板结合优异的镍基单晶高温合金沉积层,其抗拉强度为1094 MPa,伸长率为21%。Selective laser melting technology has the advantages of small spot,small heat affected zone and high forming precision,which can effectively repair nickel-based single crystal superalloy blades to prolong their service life.In this work,the alloy powder with medium volume fractionγ′phase was selected,and its microstructure evolution and mechanical properties of the alloy during epitaxial growth on single crystal CM247LC substrate were studied.The results show that,when the width-depth ratio of molten pool at the repair interface is bigger than 4,a good bonding interface and a small grain orientation difference can be formed between the deposited area and the substrate.The crack density in the deposition area can be effectively reduced by increasing the scanning speed and reducing the laser power.The deposition structure is mainly columnar dendrites growing along the deposition direction.The higher the deposition layer,the smaller the cooling rate,and the greater the dendrite spacing and grain orientation difference.By optimizing the printing parameters,a nickel-based single crystal superalloy deposit with low crack density,single grain orientation and excellent bonding with single crystal substrate was finally obtained,with tensile strength of 1094 MPa and elongation of 21%.

关 键 词：镍基单晶高温合金 选区激光熔化 显微组织 晶粒取向 力学性能 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]