缺口应力集中系数对TC4 ELI合金低周疲劳性能的影响  

Effect of Notch Stress Concentration Factors on Low-cycle Fatigue Performance of TC4 ELI Alloy

作　　者：刘天福 张滨[1] 张均锋[2] 徐强[3] 宋竹满[4] 张广平[4] LIU Tianfu;ZHANG Bin;ZHANG Junfeng;XU Qiang;SONG Zhuman;ZHANG Guangping(Key Laboratory for Anisotropy and Texture of Materials,Ministry of Education,School of Materials Science and Engineering,Northeastern University,Shengyang 110819,China;Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;China Ship Scientific Research Center,Wuxi 214082,China;Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]东北大学材料各向异性与织构教育部重点实验室、材料科学与工程学院,沈阳110819 [2]中国科学院力学研究所,北京100190 [3]中国船舶科学研究中心,无锡214082 [4]中国科学院金属研究所、沈阳材料科学国家研究中心,沈阳110016

出　　处：《材料研究学报》2023年第7期511-522,共12页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51971060,52171128)。

摘　　要：研究了缺口应力集中系数不同的深海潜水器耐压壳用TC4 ELI(Extra-low-interstitial)合金板材在恒总应变幅控制下的低周疲劳行为。结果表明,在应变幅较低(0.7%以下)和应变幅较高(0.8%和0.9%)条件下的光滑试样在循环初期分别发生了循环硬化和循环软化,而缺口试样在0.2%~0.7%应变幅条件下的循环初期均发生了循环硬化。通过循环载荷作用下材料滞回能的变化描述了TC4 ELI合金试样低周疲劳的损伤程度,得到了缺口应力集中系数与低周疲劳性能参数之间的关系,建立了相对裂纹萌生寿命预测模型。利用该模型能较好地预测缺口应力集中系数较低的TC4 ELI合金在高应变幅条件下的相对疲劳裂纹萌生寿命。The low-cycle fatigue behavior of TC4 ELI(Extra-low-interstitial)alloy plates for pressure shells in deep-sea submersible with different notch stress concentration factors under constant total strain amplitude was investigated.The results indicate that cyclic harding and cyclic softening occur in the smooth specimens under the lower strain amplitude(≤0.7%)and higher strain amplitudes(0.8%and 0.9%),respectively,at the initial stage of the cyclic loading.While the cyclic hardening occurs in all the notched specimens under the strain amplitudes of 0.2%to 0.7%at the initial stage of the cyclic loading.Based on the variation of material hysteretic energy under the cyclic loading,a relative crack initiation life prediction model was established to describe the damage degree of TC4ELI alloy specimens under the low cycle fatigue loading.The relationship between notch stress concentration factors and low cycle fatigue performance parameters was also described.This model can effectively predict the relative fatigue crack initiation life of TC4ELI alloy with low notch stress concentration factor under high strain amplitude conditions.

关 键 词：金属材料 TC4 ELI合金 低周疲劳 缺口 应力集中系数 疲劳寿命 

分 类 号：TB31[一般工业技术—材料科学与工程]