摘要
低钛铝含量的合金在强度方面表现不足,而高钛铝含量的合金在激光增材制造过程中则容易出现开裂现象。为在高γ′相体积分数和低裂纹敏感性之间取得平衡,本研究提出了一种合金成分设计思路:在高钛铝含量的IN738LC合金基础上,适当降低钛铝含量,并提高Ta含量。基于此设计思路,研究了4种不同Ta含量(1%,3%,5%,7%,质量分数)的激光增材沉积态样品及其经过固溶处理和时效处理后的组织与性能。结果表明:随着Ta含量增加,沉积态试样晶粒细化,γ′相占比增大;随着Ta含量的提高,沉积态与热处理态样品的抗拉强度与屈服强度均增加,塑性降低,开裂敏感性增高。当热处理态样品Ta的质量分数达到5%时,有η相析出;当Ta的质量分数达到7%时,试样η相过多,拉伸试样出现脆性断口,当Ta的质量分数为5%时,样品表现出塑性与强度的较优匹配(25℃下,屈服强度为962 MPa,极限抗拉强度为1 212 MPa,延伸率为11.0%;900℃下,屈服强度为410 MPa,极限抗拉强度为486 MPa,延伸率为6.1%)。通过优化Al、Ti和Ta的含量,本研究成功开发出一种以γ′相强化为主的激光增材制造镍基高温合金,实现了高γ′相体积分数与低裂纹敏感性之间的平衡,展现出优良的综合力学性能,为增材制造镍基高温合金的成分设计提供了一定参考。
Alloys with low Ti/Al content exhibit insufficient strength,while those with high Ti/Al content are prone to cracking during laser additive manufacturing.To achieve a balance between highγ′phase volume fraction and low crack susceptibility,this study proposed an alloy design strategy:appropriately reducing Ti/Al content while increasing Ta content based on the high-Ti/Al IN738LC alloy.Based on this design strategy,the microstructures and properties of four laser additive as-deposited samples with different Ta contents before and after solid solution treatment and aging treatment were studied.Results showed that with increasing Ta content,the as-deposited samples exhibited grain refine-ment and a higherγ′phase fraction.The tensile strength and yield strength of both as-deposited and heat-treated samples increased as the Ta content increased,while their ductility decreased and cracking susceptibility intensified.When the mass fraction of Ta in the heat-treated samples reached 5%,η-phase precipitation occurred.At 7%Ta content,excessiveη-phase formation led to brittle fracture surfaces in tensile specimens.Moreover,the sample with 5%Ta exhibited an optimal strength-ductility combination:at 25℃,yield strength of 962 MPa,ulti-mate tensile strength of 1212 MPa,and elongation of 11.0%;while at 900℃,yield strength of 410 MPa,ultimate tensile strength of 486 MPa,and elongation of 6.1%.Generally,through optimization of Al,Ti and Ta contents,this study successfully developed aγ′-phase strengthened laser additive manufactured nickel-based superalloy.The alloy achieved an optimal balance between highγ′-phase volume fraction and low cracking susceptibility,demonstrating excellent comprehensive mechanical properties,and these findings provided valuable insights for the compositional design of laser additive manufactured nickel-based superalloys.
作者
郭亮亮
伍文星
阳彤
陈平虎
金旭明
朱涛
邹新长
邱长军
GUO Liangliang;WU Wenxing;YANG Tong;CHEN Pinghu;JIN Xuming;ZHU Tao;ZOU Xinchang;QIU Changjun(Hunan Provincial Key Laboratory of Equipment Safety Service Technology under Abnormal Environment,University of South China,Hengyang 421001,China;Yueyang Dalu Laser Technology Co.,Ltd.,Yueyang 414000,China)
出处
《材料保护》
2025年第7期66-74,共9页
Materials Protection
基金
国家自然科学基金资助项目(52371032)
湖南省研究生科研创新项目(CX20240837)。
关键词
激光增材
镍基合金
TA
力学性能
显微组织
laser additive manufacturing
nickel-based alloy
Ta
mechanical property
microstructure
