热处理对激光增材In718/316L功能梯度材料组织和性能的影响  

Effects of Heat Treatment on Microstructure and Tensile Properties of Laser Additive Manufactured In718/316L Functionally Gradient Material

作　　者：吴润宝 徐刚[1] 罗开玉[1] 王长雨 鲁金忠[1] WU Runbao;XU Gang;LUO Kaiyu;WANG Changyu;LU Jinzhong(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013)

机构地区：[1]江苏大学机械工程学院,镇江212013

出　　处：《机械工程学报》2022年第19期293-305,共13页Journal of Mechanical Engineering

基　　金：国家自然科学基金(52175409);江苏省重点研发计划(产业前瞻与关键核心技术)重点(2022069-4);江苏省六大人才高峰(2019-GDZB-251)资助项目。

摘　　要：研究1 080℃(HT1)和980℃(HT2)固溶温度的固溶双时效处理对激光定向能量沉积(Laser directed energy deposition,LDED)的In718/316L功能梯度材料(Functionally gradient material, FGM)微观组织的影响,以揭示热处理诱导的微观组织演变对In718/316L FGM硬度和拉伸性能的影响机理。结果表明,随着In718粉末含量的增加,In718/316L FGM的微观组织沿增材方向呈现由等轴晶向柱状晶的转化,固溶双时效热处理后,In718/316L FGM中的铁素体含量降低,同时在靠近In718的区域析出大量的γ′、γ″和δ强化相。HT2试样的晶粒比HT1试样的更细。随着In718粉末含量的增加,In718/316L FGM的硬度呈现出先减后增的趋势,热处理后,随着γ′和γ″等强化相的析出,In718/316L FGM的整体显微硬度、抗拉强度和塑性得到显著提高。热处理前后试样都以韧性断裂为主,但热处理后韧性特征更为显著。相比之下,HT2热处理后In718/316L FGM的强塑性配比更佳。The effects of solution double aging heat treatment at solution temperatures of the 1 080 ℃(HT1) and 980 ℃(HT1) on the microstructure of laser directed energy deposited(LDEDed) In718/316L functionally gradient material(FGM) is investigated to reveal the mechanism of heat treatment-induced microstructure evolution on the microhardness and tensile properties of In718/316L FGM. The results show that the microstructure of In718/316L FGM changes from equiaxed grain to columnar grain in building direction with the increase of In718 powder content. After the solution double aging heat treatment, the ferrite content of In718/316L FGM is reduced, and a large amount of γ′, γ″, and δ phases are precipitated in the region closed to 100 vol% In718. The grains of the HT2 specimen are smaller than those of the HT1 specimen. With the increase of In718 powder content, the microhardness of In718/316L FGM is decreased firstly and then increased. After heat treatment, the microhardness, strength and the plasticity of In718/316L FGM are significantly improved with the precipitation of the enhanced γ′and γ″phase. The specimens before and after heat treatment are mainly by ductile fracture, but the ductile characteristics are more significant after heat treatment. In contrast, the strength and plastic matching of In718/316L FGM was more superior after HT2 heat treatment.

关 键 词：激光定向能量沉积 In718/316L 功能梯度材料 热处理 拉伸性能 显微组织 

分 类 号：TG156[金属学及工艺—热处理]