Effects of solution treatment on grain coarsening and hardness of laser welds in UNS N10003 alloy contained different carbon content  

作　　者：Kun Yu Xianwu Shi Zhenguo Jiang Chaowen Li Shuangjian Chen Wang Tao Xingtai Zhou Zhijun Li 

机构地区：[1]Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China [2]University of Chinese Academy of Sciences, Beijing 100049, China [3]State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China

出　　处：《Journal of Materials Science & Technology》2019年第8期1719-1726,共8页材料科学技术（英文版）

基　　金：supported by the National Key Research and development program of China (2016YFB0700404);the National Natural Science (Grant Nos. 51371188, 51671122, 51671154, 51501216 and 51601213);the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA02004210)

摘　　要：Microstructure and microhardness evolution of laser welds in low carbon UNS N10003 alloy(LC alloy)and high carbon UNS N10003 alloy(HC alloy)before and after solution treatment have been characterized and investigated in this work.The eutectic M6C-γ carbides have been transformed into spherical M6C carbides in fusion zone of HC alloy,while it can be found that the spherical M6C carbides were precipitated in fusion zone of LC alloy after solution treatment.The grain coarsening of fusion zone in HC alloy was slight because the migration of grain boundaries were impeded by the eutectic M6C-γ carbides.However,the columnar grains of fusion zone in LC alloy were transformed into the coarse equiaxed grains due to the migration of grain boundaries were not impeded.The activation energy of grain growth between 1093℃ and 1177℃ for 20 min in LC fusion zone was 144.3 kJ mol^-1,while that of HC fusion zone was 309.5 kJmol^-1 calculated according to the classical Arrhenius equation.The microhardness of fusion zone in LCalloy was lower than that of fusion zone in HC alloy after solution treatment because of no dispersion strengthening and grain coarsening.Microstructure and microhardness evolution of laser welds in low carbon UNS N10003 alloy（LC alloy）and high carbon UNS N10003 alloy（HC alloy）before and after solution treatment have been characterized and investigated in this work.The eutectic M6C-γ carbides have been transformed into spherical M6C carbides in fusion zone of HC alloy,while it can be found that the spherical M6C carbides were precipitated in fusion zone of LC alloy after solution treatment.The grain coarsening of fusion zone in HC alloy was slight because the migration of grain boundaries were impeded by the eutectic M6C-γ carbides.However,the columnar grains of fusion zone in LC alloy were transformed into the coarse equiaxed grains due to the migration of grain boundaries were not impeded.The activation energy of grain growth between 1093℃ and 1177℃ for 20 min in LC fusion zone was 144.3 kJ mol-1,while that of HC fusion zone was 309.5 kJmol-1calculated according to the classical Arrhenius equation.The microhardness of fusion zone in LCalloy was lower than that of fusion zone in HC alloy after solution treatment because of no dispersion strengthening and grain coarsening.

关 键 词：MOLTEN salt reactor Nickel base ALLOY LASER welding M6C Grain COARSENING 

分 类 号：TG[金属学及工艺]