Investigation of interfacial strength evolution in dissimilar metal bonding and its application to a new bonding process

2016 Fiscal Year Final Research Report

• Project/Area Number: 26249099
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Composite materials/Surface and interface engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Koseki Toshihiko 東京大学, 大学院工学系研究科(工学部), 教授 (70361532)
• Co-Investigator(Renkei-kenkyūsha): INOUE Junya 東京大学, 大学院工学系研究科, 准教授 (70312973) ; NAMBU Shoichi 東京大学, 大学院工学系研究科, 講師 (00529654) ; OJIMA Mayumi 東京大学, 大学院工学系研究科, 助教 (80569799)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 異種金属 / 接合 / 固相接合 / 界面 / 界面強度 / 分子動力学

Outline of Final Research Achievements

This study aims at clarifying the bonding mechanism of dissimilar metals at low temperatures and designing a new joining process of dissimilar metals that enables multi-material structures. For the purpose, steel-to-steel and steel-to-nickel combinations were warm-compressed and isothermally held, and the microstructure of the bonding interface and its strength were investigated. It was found that the evolution of the interfacial strength consisted of two stages; strength increase without increase in contact area of the interface (stage I) and the following strength increase with increasing the contact area (stage II). Analysis of strain distribution at the bonding interface and molecular dynamic simulation of the bonding process reveals that the rearrangement of atoms and decrease in compressed strain proceed in the stage I, which increases the interfacial strength without increase in contact area. The importance of isothermal holding after the compressive bonding is indicated.

Free Research Field

金属工学、接合工学