Experimental and numerical analyses for elucidation of formation mechanism of magnetic pulse welded dissimilar metal joint interface and establishment of optimum welding conditions

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05028
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Kumai Shinji 東京工業大学, 物質理工学院, 教授 (00178055)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 接合・溶接 / 構造・機能材料 / 異種金属接合 / 数値解析 / 衝撃圧接 / 接合機構 / 接合条件

Outline of Final Research Achievements

Mutual relationship among welding conditions, joint interface morphologies of dissimilar metals and their joint strength was investigated by using both experimental and numerical analyses. The numerical analysis combining an impact analysis and a thermal analysis was effective to reproduce the material distribution (mixing behavior of two metals) at the collision point, abrupt and sharp increase in pressure and temperature at the joint interface, and a rapid cooling behavior at the joint interface due to the thermal diffusion after the collision. The reproduced joint interface morphology by the simulation showed a good quantitative agreement with that of the experimentally obtained dissimilar metal joint interface. These results indicate that the approach used in the present study was useful to reveal the formation mechanism of the magnetic pulse welded interface and establish the optimum welding condition for producing strong and reliable dissimilar metal joints.

Free Research Field

接合、鋳造、組織制御、力学的性質、疲労、破壊、軽金属

Academic Significance and Societal Importance of the Research Achievements

異種金属接合は製品のマルチマテリアル化に欠かせないが、通常の溶融接合法や固相接合法は熱影響による組織変化や特性劣化が大きいため、異種金属接合には適用できない。電磁圧接は電磁力により異種金属を高速で傾斜衝突させ、固相状態で瞬間的に接合させる手法であり、どのような金属でも極めて強固に接合できる。本研究では、数μ秒間という極めて短時間に起こる金メタルジェットの放出と波状界面形成、局所的圧力・温度上昇とその後の急速冷却過程を数値解析して再現した接合界面が、実際の接合界面と極めてよく一致することを示したものであり、接合界面形成メカニズムの解明という学術的意義、最適接合条件の確立という社会的意義がある。