激光功率对一种新型增材制造专用镍基高温合金显微组织和拉伸性能的影响  

Influence of laser power on microstructure and tensile property of a new nickel-based superalloy designed for additive manufacturing

作　　者：吴彬[1,2] 梁静静 周亦胄 杨彦红 李金国 孙晓峰[1] Bin WU;Jing-jing LIANG;Yi-zhou ZHOU;Yan-hong YANG;Jin-guo LI;Xiao-feng SUN(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China;Key Laboratory of Space Manufacturing Technology,Chinese Academy of Sciences,Beijing 100094,China)

机构地区：[1]中国科学院、金属研究所、师昌绪先进材料创新中心,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016 [3]中国科学院太空制造技术重点实验室,北京100094

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第4期1124-1143,共20页中国有色金属学报（英文版）

基　　金：the financial supports from the National Science and Technology Major Project,China(No.Y2019-VII-0011-0151);the National Natural Science Foundation of China(No.51771190)。

摘　　要：研究在不同激光功率下某一新型增材制造专用高温合金的组织和拉伸性能。通过X射线衍射和电子扫描显微镜等手段,证实合金不含明显裂纹;合金组织由典型的定向生长非平衡凝固的枝/胞晶组织构成。枝晶间和枝晶干分别富集元素Nb、Si、Ti和Al、Cr、Co。当激光功率较低时,合金的胞状晶排列整齐,一次枝晶间距(PDAS)小,孔隙率大,强度高、伸长率低;随着激光功率的增加,PDAS增大,孔隙率降低,强度下降、伸长率提高;当激光功率更大时,Marangoni对流效应增强并对组织和性能产生独特的影响,导致合金的胞状晶排列趋于紊乱,同时PDAS减小,孔隙率较大,强度值较高、伸长率较低。合金小的PDAS有利于减弱元素微观偏析、细化组织、提高合金强度。拟合了PDAS和屈服强度(YS)的关系公式,探讨了合金组织中同心花样环的形成机制。The microstructure and tensile properties of a new Ni-based superalloy specially designed for additive manufacture(AM)were investigated under different laser power(LP)conditions.The results measured by X-ray diffraction analysis and scanning electron microscopy show that no cracks are observed in as-deposited alloy,which has typical crystallography orientation and non-equilibrium solidification dendrite/cellular morphology.The elements such as Nb,Si and Ti are enriched in the interdendritic regions,while Al,Cr and Co segregate in the dendritic cores.When the LP is low,the cellular crystals of the alloy are arranged orderly,the primary dendrite arm space(PDAS)is small,the porosity is large,the strength is high and the elongation is low.With the increase of LP,the PDAS increases,the porosity decreases,the strength decreases and the elongation increases.When the LP is elevated further,Marangoni convection effect is enhanced and shows unique impacts,that is,the disordered arrangement of cellular crystals occurs.Then,the PDAS decreases,the porosity increases,the strength increases and the elongation decreases.The smaller PDAS favors the reduction for elements segregation,as well as microstructure refinement and strength improvement.The fittingformula between PDAS and yield strength(YS)was proposed,and the concentric ring patterns inside microstructure were rationalized.

关 键 词：Marangoni对流 熔池 激光功率 一次枝晶间距(PDAS) 偏析 

分 类 号：TG132.3[一般工业技术—材料科学与工程] TG665[金属学及工艺—合金]