Effects of filling material and laser power on the formation of intermetallic compounds during laser-assisted friction stir butt welding of steel and aluminum alloys

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• 作者：Xinjiang Fei ; Xiangzhong Jin ; Nanxiang Peng ; Ying Ye ; Sigen Wu…
• 刊名：Applied Physics A: Materials Science & Processing
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：122
• 期：11
• 全文大小：2,308 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Condensed Matter
  Optical and Electronic Materials
  Nanotechnology
  Characterization and Evaluation Materials
  Surfaces and Interfaces and Thin Films
  Operating Procedures and Materials Treatment
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-0630
• 卷排序：122

文摘

In this paper, two kinds of materials, Ni and Zn, are selected as filling material during laser-assisted friction stir butt welding of Q235 steel and 6061-T6 aluminum alloy, and their influences on the formation of intermetallic compounds on the steel/aluminum interface of the joints were first studied. SEM was used to analyze the profile of the intermetallic compound layer and the fractography of tensile fracture surfaces. In addition, EDS was applied to investigate the types of the intermetallic compounds. The results indicate that a thin iron-abundant intermetallic compound layer forms and ductile fracture mode occurs when Ni is added, but a thick aluminum-abundant intermetallic compound layer generates and brittle fracture mode occurs when Zn is added. So the tensile strength of the welds with Ni as filling material is greater than that with Zn as filling material. Besides, the effect of laser power on the formation of intermetallic compound layer when Ni is added was investigated. The preheated temperature field produced by laser beam in the cross section of workpiece was calculated, and the tensile strength of the joints at different laser powers was tested. Results show that only when suitable laser power is adopted, can suitable preheating temperature of the steel reach, then can thin intermetallic compound layer form and high tensile strength of the joints reach. Either excessive or insufficient laser power will reduce the tensile strength of the joints.