孔隙类型对激光选区熔化Inconel 625合金高温塑性的影响  

Effect of Pore Type on High⁃Temperature Plasticity of Inconel 625 Alloy Fabricated by Selective Laser Melting

作　　者：聂伟 刘奋成 胡文伟 刘丰刚 耿永祥 王宏 胡万谦 王联波 Nie Wei;Liu Fencheng;Hu Wenwei;Liu Fenggang;Geng Yongxiang;Wang Hong;Hu Wanqian;Wang Lianbo(National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology,Nanchang Hangkong University,Nanchang 330063,Jiangxi,China;Engineering Training Centre,Nanchang Hangkong University,Nanchang 330063,Jiangxi,China;Jiangxi Baohang Advanced Materials Co.Ltd.,Nanchang 330200,Jiangxi,China)

机构地区：[1]南昌航空大学轻合金加工科学与技术国防重点学科实验室,江西南昌330063 [2]南昌航空大学工程训练中心,江西南昌330063 [3]江西宝航新材料有限公司,江西南昌330200

出　　处：《中国激光》2024年第10期314-324,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金(52361010,52265053);南昌航空大学研究生创新专项资金(YC2022-037);轻合金加工科学与技术国防重点实验室开放基金(EG202101419);无损检测教育部重点实验室开放基金(EW202203364)

摘　　要：采用激光选区熔化成形了Inconel 625合金试样,研究了激光功率和扫描速度对合金孔隙的影响,制备了存在大尺寸圆形孔隙缺陷(key-hole模式下)、小尺寸圆形孔隙缺陷(conduction模式下)和不规则孔隙缺陷的拉伸试样,通过815℃高温拉伸试验探讨了孔隙类型对合金抗拉强度及塑性的影响。结果表明:孔隙类型对合金815℃高温抗拉强度及塑性有较大影响。其中,不规则孔隙缺陷试样的高温抗拉强度为374 MPa,塑性为5%;大尺寸圆形孔隙缺陷试样的高温抗拉强度为364 MPa,塑性为31%;小尺寸圆形孔隙缺陷试样的高温抗拉强度为363 MPa,塑性为37%。当不规则孔隙向小尺寸圆形孔隙转变时,高温抗拉强度约降低3%;当大尺寸圆形孔隙向小尺寸圆形孔隙转变时,高温塑性约提升19%。在各类815℃高温拉伸试样断口纵截面中均发现了大量的沿晶界扩展的高温失塑裂纹,这是合金失塑的主要原因。孔隙缺陷处的位错塞积造成较大的应力集中,阻挡了位错滑移和合金的塑性变形,使合金更易发生断裂。Objective Inconel 625 superalloy is extensively used in combustion turbines because of its superior tensile,fatigue,and creep strengths at elevated temperatures.Selective laser melting(SLM),which is one of the most promising additive manufacturing(AM)methods for hightemperature superalloys,has attracted considerable attention in many fields,including aerospace,owing to its special technical advantages.However,plastic loss occurs in the service temperature range of nickelbased superalloys,which poses a serious threat to the stability of their mechanical properties during service.To ensure the stability of SLMfabricated Inconel 625 superalloy in hightemperature service environments,the different types of pore defects should be studied to understand the hightemperature plastic deformation behavior of this superalloy for engineering applications.Methods Different types of pore defect samples are prepared by adjusting the process parameters,and the samples are subjected to room-and hightemperature tensile tests.The influence of different types of pore defects on the hightemperature plastic loss of the superalloy is analyzed using fracture and fracture longitudinal sections,and the fracture mechanism is analyzed.Results and Discussions When the laser power is set to 300 W,with increasing scanning speed,the pore defects transit from large regular circular pore defects in“keyhole”mode to small regular circular pore defects in“conduction”mode.When the scanning speed is further increased,the laser energy input decreases,and irregular pore defects with typical tip shapes are obtained(Fig.3).In the tensile test,the influence of different pore types on the room-temperature plasticity and hightemperature plasticity of the alloy becomes more apparent.Among these pore types,irregular incomplete fusion defects exert the greatest impact on plasticity,with roomtemperature plasticity and hightemperature plasticity of 6.47%and 4.85%,respectively.The second most influential defects are the large circular pores in the“keyhole

关 键 词：激光技术 激光选区熔化 Inconel 625合金 孔隙缺陷 高温失塑行为 

分 类 号：TG457.1[金属学及工艺—焊接]