激光增材制造 SS316L/Inconel718 功能梯度材料的组织、性能表征与热力学分析

MICROSTRUCTURE, PROPERTIES AND THERMODYNAMIC ANALYSIS OF SS316L/Inconel718 FGM FABRICATED BY LASER ADDTIVE MANUFACTURING

唐茂倍

11930445

硕士

材料工程

刘朝阳

2021-05-20

2021-06-07

南方科技大学

深圳

传统的金属材料零部件使用工况条件简单，在使用时只需要考虑其屈服强度，硬度，塑性、韧性等简单的力学性能即可。但随着科学技术的发展以及工业的进步，在航空航天、核电、机械工程、光学工程、生物医学等领域所需要使用的材料面临的工况条件是复杂且苛刻的，对材料综合性能要求更高。在这种背景下急需发展能够满足复杂且严苛的工况条件下使用的高性能金属材料。SS316L不锈钢由于良好的加工性能和耐腐蚀性能而在工业领域有着广泛的应用，Inconel718合金在航空航天领域也有着广泛的应用，两者结合的功能梯度材料可作为耐高温以及大温差反复热冲击的材料，具有良好的应用前景。本文主要研究内容如下：（1）使用激光增材制造工艺制备了SS316L不锈钢和镍基高温合金Inconel718合金的功能梯度材料，并对其微观组织变化情况、相变化情况以及力学性能进行了分析。（2）对功能梯度材料梯度界面出现的主要缺陷—裂纹进行了形貌观测和微区元素分析。使用扫描电镜（SEM）、能谱（EDS）分析了裂纹缺陷的形貌，裂纹主要元素成分，使用电子背散射衍射（EBSD）检测方法分析了功能梯度材料裂纹成因，通过这些检测分析手段进一步的解释了裂纹出现的成因及扩展方式。（3）使用热力学计算软件Thermo-calc对功能梯度材料梯度界面的各个梯度成分的析出过程进行了计算，得出了各个梯度成分的析出相的析出过程，以及析出相的相对含量、凝固过程以及有害相的相对含量的情况。最后根据对裂纹的分析以及热力学数据的分析以及梯度成分薄壁试样的验证实验结果，设计了优化SS316L /Inconel718梯度材料界面过渡的方案。并按照方案制备了SS316L/Inconel718功能梯度材料薄壁结构，对薄壁结构进行了组织分析、硬度分析，对方案的功能梯度材料性能进行了验证。

The traditional working conditions of metal parts are simple, and only the yield strength, hardness, plasticity and toughness of the parts can be considered. But with the development of science and technology and the progress of industry, the working conditions of materials needed in aerospace, nuclear power, mechanical engineering, optical engineering, biomedical and other fields are complex and demanding, and the requirements for comprehensive properties of materials are higher. In this context, it is urgent to develop high performance metal materials which can meet the complex and severe working conditions. SS316L stainless steel has been widely used in industry because of its good processing and corrosion resistance. Inconel718 alloy has been widely used in aerospace field. The functional gradient material combined with the two can be used as the material of high temperature and repeated thermal shock with large temperature difference, which has a good application prospect.The main contents of this paper are as follows:(1) The functional gradient materials of SS316L stainless steel and nickel base superalloy Inconel718 were prepared by laser addition technology. The microstructure, phase change and mechanical properties of SS316L stainless steel were analyzed.(2) The morphology of the crack, the main defect in gradient interface of FGM, was observed. The morphology of the crack was analyzed by SEM and EDS, and the crack elements were analyzed by EBSD. The crack causes of the FGM were further explained by these detection and analysis methods The causes and the ways of expansion.(3) The precipitation process of the gradient components in the gradient interface of functionally graded materials is calculated by thermocalc software. The precipitation process of the precipitates of each gradient component, the relative content of the precipitates, the solidification process and the relative content of the harmful phase are obtained.Finally, based on the analysis of crack and thermodynamic data and the experimental results of thin-walled samples with gradient composition, the optimization SS316L is designed /The interface transition scheme of Inconel718 gradient material was designed and the thin-walled structure of ss316l/inconel718 functional gradient material was prepared according to the scheme. The microstructure and hardness analysis of thin-walled structure were carried out, and the performance of functional gradient material was verified.

功能梯度材料 激光增材制造 裂纹 热力学分析

Functionally graded materials Laser additive manufacturing Crack Thermodynamic analysis

中文

独立培养

南方科技大学

唐茂倍. 激光增材制造 SS316L/Inconel718 功能梯度材料的组织、性能表征与热力学分析[D]. 深圳. 南方科技大学,2021.