摘要
针对镍基高温合金TIG电弧增材存在组织及性能各向异性的共性难题,提出采用步进填丝双脉冲钨极氩弧焊(Double-Pulse-TIG,DP-TIG)方法开展了Inconel718镍基高温合金的增材制造试验,重点研究分析了高频脉冲电流振幅对增材件组织及性能的影响规律。利用红外热成像仪测量了熔池温度场,并结合电子背散射衍射(Electron Back Scatter Diffraction,EBSD)图像揭示了微观组织演变的内在热力学原因。通过拉伸试验表征了试件力学性能变化,并分析了断口形貌特征。研究结果表明:当高频脉冲电流幅值由20 A增加到100 A时,熔池温度梯度G减小,熔池凝固速率R增大,凝固参数G×R和G/R都减小,组织向等轴晶方向转变;平均晶粒大小由56.2μm减小到49.7μm,在<001>方向上的取向密度从21.16增加到28.32;横向抗拉强度基本保持不变,约为740 MPa;纵向抗拉强度由729 MPa增加到756 MPa。高频脉冲电流幅值调控可以弱化增材件各向异性,横纵向塑韧性明显改善增强。
Aiming at solving the anisotropy of microstructure and properties commonly existing in traditional arc welding,the component of Inconel 718 was additive manufactured by double-pulse-TIG(DP-TIG).The influence by the amplitude of high frequency pulse current on the microstructure and properties of the components is specially studied.The temperature field of molten pool was got by infrared thermal imager,and the thermodynamic reasons of microstructure evolution were revealed by Electron Back Scatter Diffraction(EBSD).The mechanical properties of the samples were characterized by tensile test,and the fracture morphology was analyzed.The results show that when the amplitude of high frequency pulse increases from 20 A to 100 A,the temperature gradient G of molten pool decreases,the solidification rate R of molten pool increases,the solidification parameters G×R and G/R decrease,and the microstructure changes to equiaxed crystal;The average grain size decreased from 56.2μm to 49.7μm,and the orientation density on the<001>direction increased from 21.16 to 28.32;The horizonal tensile strength is about 740 MPa which is nearly constant.The vertical tensile strength increased from 729 MPa to 756 MPa.By controlling the amplitude of high frequency pulse current,the anisotropy of the components is weakened and the plasticity and toughness in both transverse and longitudinal directions is enhanced.
作者
张程
张刚
刘忠义
石玗
魏涛
ZHANG Cheng;ZHANG Gang;LIU Zhongyi;SHI Yu;WEI Tao(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou 730050,China;Harbin Welding Institute Limited Company,Harbin 150028,China)
出处
《电焊机》
2025年第7期36-42,56,共8页
Electric Welding Machine
基金
国家自然科学基金(52265050)
甘肃省科技重大专项(22ZD6GA008)。
