Improved distortion prediction in additive manufacturing using an experimental-based stress relaxation model

作     者：Ruishan Xie Qingyu Shi Gaoqiang Chen Ruishan Xie;Qingyu Shi;Gaoqiang Chen

作者机构：State Key Laboratory of TribologyDepartment of Mechanical EngineeringTsinghua UniversityBeijing 100084China Key Laboratory for Advanced Material Processing TechnologyMinistry of EducationBeijing 100084China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2020年第59卷第24期

页      面：83-91页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：financially supported by the National Key Technologies Research and Development Program,China(No.2016YFB1100100) the China Scholarship Council。 

主　　题：Additive manufacturing Welding Thermo-mechanical modeling Distortion prediction Stress relaxation 

摘      要：In additive manufacturing(AM),numerous thermal cycles make stress relaxation a significant factor in affecting the material mechanical response.However,the traditional material constitutive model cannot describe repeated annealing behavior.Here,we propose an improved constitutive model based on a serial of stress relaxation experiments,which can descript the temperature and time-dependent stress relaxation behavior during AM.By using the proposed relaxation model,the prediction accuracy is significantly improved due to the recovery of inelastic strain during multilayer deposition.The results are validated by both in-situ and final distortion measurements.The influence mechanism of the relaxation behavior on material mechanical response is explained by the three-bar model in thermo-elastic-plastic theory.The relaxation behavior during the whole AM process is clarified.The stress behavior is found to have a limited effect when merely depositing several layers;nevertheless,it becomes a prominent impact when depositing multiple layers.The proposed model can enhance modeling accuracy both in AM and in multilayer welding.