拉伸变形和热处理对GH4169镍基高温合金应变速率敏感性的影响  

Effect of tensile deformation and heat treatment on strain rate sensitivity of nickel-based superalloy GH4169

作　　者：郑泽邦 旷野 赵盼娣 宋晓悦 Zheng Zebang;Kuang Ye;Zhao Pandi;Song Xiaoyue(Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西北工业大学材料学院陕西省高性能精确塑性成形技术与装备重点实验室,陕西西安710072

出　　处：《锻压技术》2024年第7期48-56,共9页Forging & Stamping Technology

基　　金：国家自然科学基金资助项目(52105399)。

摘　　要：通过对GH4169镍基高温合金轧制板材分别施加5%、15%、25%的拉伸变形以及变形后退火热处理,模拟W型金属密封环制造过程中的变形特征,并采用0.1、0.01、0.001 s^(-1)3种应变速率分别对拉伸变形及热处理后的GH4169镍基高温合金进行拉伸实验,结合微观组织表征及疲劳测试,研究了拉伸变形与热处理对GH4169镍基高温合金应变速率敏感性及疲劳响应等力学行为的影响规律。结果表明,在拉伸变形方面,材料在拉伸过程中会产生明显硬化现象,且变形量越大,卸载后再拉伸的屈服强度越高,硬化速率越小,应变速率敏感性越强;但拉伸变形对材料的弹性模量与极限强度的影响不大,且硬化速率与应变速率无关。在热处理方面,950℃的退火热处理会使15%拉伸变形试样的平均晶粒尺寸增大,织构强度增加,且伴有少量退火孪晶的产生;退火后试样的屈服强度降低,塑性和硬化速率均提高,但应变速率敏感性降低,其力学性能介于未变形状态和拉伸变形状态之间。在疲劳响应方面,退火热处理能够降低材料在疲劳载荷作用下的塑性应变累积,从而改善其疲劳性能,这种改善效果在疲劳循环前期更显著。The deformation characteristics during the manufacturing process of W-shaped metal sealing rings were simulated by applying tensile deformations of 5%,15%and 25%,and annealing heat treatment after deformation to nickel-based superalloy GH4169 rolled plate.Then,the uniaxial tensile tests under the strain rates of 0.1,0.01 and 0.001 s^(-1)were conducted on the deformed and heat-treated nickel-based superalloy GH4169,and the influence laws of tensile deformation and heat treatment on the mechanical behavior,such as strain rate sensitivity and fatigue response of nickel-based superalloy GH4169 were investigated by combining microstructural characterization and fatigue testing.The results show that in terms of tensile deformation,the material exhibits significant hardening during the tensile deformation process,and the larger the deformation,the higher the yield strength after unloading and then stretching,the smaller the hardening rate,the stronger the strain rate sensitivity.However,the tensile deformation has little effect on the elastic modulus and ultimate strength of the material,and the hardening rate is independent of the strain rate.Regarding heat treatment,annealing at 950℃increases the average grain size and texture intensity of the 15%tensile-deformed specimens,and accompanied by the formation of a small number of annealing twins.After annealing,the yield strength of specimens reduces,and the plasticity and hardening rate increase,but the strain rate sensitivity decreases,with the mechanical properties between the undeformed and tensile-deformed states.In terms of fatigue response,the annealing heat treatment reduces the accumulation of plastic strain under the action of fatigue loading,thereby improves the fatigue performance of the material,which appears a more significant improvement effect in the early stages of fatigue cycle.

关 键 词：镍基高温合金 金属密封环 应变速率敏感性 拉伸变形 退火 疲劳 

分 类 号：TG113.25[金属学及工艺—物理冶金]