Microstructural analyses of aluminum–magnesium–silicon alloys welded by pulsed Nd: YAG laser welding

作     者：Hossain Ebrahimzadeh Hassan Farhangi Seyed Ali Asghar Akbari Mousavi Arman Ghahramani Hossain Ebrahimzadeh;Hassan Farhangi;Seyed Ali Asghar Akbari Mousavi;Arman Ghahramani

作者机构：School of Metallurgy and Materials EngineeringCollege of EngineeringUniversity of TehranTehran 11155-4563Iran 

出 版 物：《International Journal of Minerals,Metallurgy and Materials》 (矿物冶金与材料学报（英文版）)

年 卷 期：2020年第27卷第5期

页      面：660-668页

核心收录：

学科分类：080503[工学-材料加工工程] 0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 0806[工学-冶金工程] 0708[理学-地球物理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0702[理学-物理学] 0801[工学-力学（可授工学、理学学位）] 080201[工学-机械制造及其自动化] 

基　　金：The authors would like to thank the metallography laboratory personnel of University of Tehran for their cooperation 

主　　题：etching technique laser welding inter-dendritic spacing grain size aluminum–magnesium–silicon alloys hot crack formation model 

摘      要：Revealing grains and very fine dendrites in a solidified weld metal of aluminum–magnesium–silicon alloys is difficult and thus,there is no evidence to validate the micro-and meso-scale physical models for hot cracks. In this research, the effect of preheating on the microstructure and hot crack creation in the pulsed laser welding of AA 6061 was investigated by an optical microscope and field emission electron microscopy. Etching was carried out in the gas phase using fresh Keller’s reagent for 600 s. The results showed that the grain size of the weld metal was proportional to the grain size of the base metal and was independent of the preheating temperature. Hot cracks passed the grain boundaries of the weld and the base metal. Lower solidification rates in the preheated samples led to coarser arm spacing;therefore, a lower cooling rate. Despite the results predicted by the micro and meso-scale models, lower cooling rates resulted in increased hot cracks. The cracks could grow in the weld metal after solidification;therefore, hot cracks were larger than predicted by the hot crack prediction models.