GH4169合金拘束相关的疲劳裂纹萌生寿命  

Constraint Related Fatigue Crack Initiation Life of GH4169 Superalloy

作　　者：郭昊函 杨杰 刘芳[2] 卢荣生 GUO Haohan;YANG Jie;LIU Fang;LU Rongsheng(School of Energyand Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;School of Mechanical Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Key Laboratoryof Pressure Systems and Safety,Ministryof Education,East China University of Scienceand Technology,Shanghai 200237,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]上海理工大学机械工程学院,上海200093 [3]华东理工大学承压系统与安全教育部重点实验室,上海200237

出　　处：《金属学报》2022年第12期1633-1644,共12页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51975378;上海市浦江人才计划项目No.21PJD047。

摘　　要：以GH4169镍基高温合金为研究对象,基于低周疲劳率相关的晶体塑性本构,引入累积能量耗散和累积塑性滑移2种疲劳指示因子作为疲劳裂纹萌生判据,对不同微缺口深度和长度下的疲劳裂纹萌生寿命进行研究。并基于统一拘束参数A_(p),进一步考察拘束与疲劳裂纹萌生寿命的关联。结果表明:2种疲劳指示因子均可较好地预测疲劳裂纹萌生寿命。随着微缺口深度的增加,疲劳裂纹萌生寿命逐渐减少;随着微缺口长度的增加,疲劳裂纹萌生寿命逐渐增加。在不同的微缺口深度和长度下,疲劳裂纹萌生寿命均与√Ap存在线性关系。可以根据该线性关系,确定拘束相关的疲劳裂纹萌生寿命。Nickel-based GH4169 superalloy is used as turbine disc material in aeroengines because of its good oxidation resistance, good formability, weldability, and high strength. However, turbine disc fatigue failure will inevitably occur in onerous service environments and after a long operation time. To ensure the safety and reliability of aeroengines, the fatigue damage behavior and fatigue life of GH4169 superalloy need to be studied. Constraint is an important factor affecting the fatigue fracture behavior of materials, because changing it will impact the fatigue behavior. To achieve a long service life and high reliability of aeroengines, fatigue and constraint effects must be researched. However, there are only limited studies on the effect of constraint on fatigue crack initiation time. In this study, a crystal plasticity constitutive model based on low cycle fatigue rate correlation was applied to the GH4169 superalloy. Two fatigue indicators, namely the cumulated energy dissipation and cumulated plastic slip, were introduced as fatigue crack initiation criteria to study the fatigue crack initiation time for different micro-notch depths and lengths. In addition, the relationship between constraint and fatigue crack initiation life was further investigated using the unified constraint parameter A_(p). The results showed that both cumulated energy dissipation and cumulated plastic slip can accurately predict the fatigue crack initiation time. With the increase in micro-notch depth, the fatigue crack initiation time decreased, while it increased with the increase in micro-notch length. A linear relationship between the fatigue crack initiation time and √Ap under different micro-notch depths and lengths was observed. Based on this relationship, the constraint related to the fatigue crack initiation time can be determined.

关 键 词：拘束 疲劳裂纹 萌生寿命 晶体塑性 累积能量耗散 累积塑性滑移 

分 类 号：TH114[机械工程—机械设计及理论]