文献类型：期刊文献

英文题名：Effect of preheating on the microstructure and properties of fiber laser welded girth joint of thin-walled nanostructured Mo alloy

作者：Zhang, Lin-Jie[1];Liu, Jiang-Zhe[1];Bai, Qing-Lin[1];Wang, Xue-Wu[2];Sun, Yuan-Jun[1,3];Li, Si-Gong[4];Gong, Xing[4]

机构：[1]Xi An Jiao Tong Univ, State Key Lab Mech Behav Mat, Xian 710049, Shaanxi, Peoples R China;[2]East China Univ Sci & Technol, Sch Informat Sci & Engn, Shanghai 200237, Peoples R China;[3]Jinduicheng Molybdenum Co Ltd, Ctr Tech, Xian 710077, Shaanxi, Peoples R China;[4]China Nucl Power Technol Res Inst, Shenzhen 518124, Peoples R China

年份：2019

卷号：78

起止页码：219

外文期刊名：INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS

收录：;EI(收录号：20184105925599);WOS:【SCI-EXPANDED(收录号:WOS:000451489300026)】；

基金：This work was supported by the National Natural Science Foundation of China (Grant Nos. 51775416 and 61773165), National Thousand Talents Program of China (Grant No. WQ2017610446) and Natural Science Foundation of Shaanxi Province (Grant No. 2017JM5069).

语种：英文

外文关键词：Nanostructured Mo alloy; Girth joint; Fiber laser welding; Preheating; Microstructure; Mechanical properties

摘要：Fiber laser girth welding of a thin-walled nanostructured Mo (NS-Mo) alloy tube was conducted. The microstructures, properties, and residual stresses of the welded girth joints achieved at different preheating temperatures were compared. Combining finite element simulation with experimental data, it was found that as the preheating temperature increased, the maximum welding residual tensile stress monotonically decreased while the tensile strength of the joints increased at first and then declined. At the preheating temperature of 673 K, the tensile strength reached a maximum, which was approximately 50% that of the base metal. The results showed that oxygen content was segregated at the grain boundary of fusion zone during welding and further produced Mo oxides. As the preheating temperature increased, vaporized Mo oxides might escaped from the molten pool, so the oxygen concentration at the grain boundary first decreased. However, when the preheating temperature increased over 773 K, the oxygen concentration rose due to the increased oxidation tendency of Mo at high temperatures and grains in the fusion zone coarsened greatly, while the total area of grain boundaries reduced.