Diffusion Welding of Fiber-reinforced Metal Matrix Composite

Research Project

Project/Area Number	60550525
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	溶接工学
Research Institution	Osaka University
Principal Investigator	IKEUCHI Kenji Research Instructor, Welding Research Institute of Osaka University, 溶接工学研究所, 助手 (10030058)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	Diffusion welding / Fiber-reinforced metal matrix composite / Alumina / Aluminum-magnesium-silicon alloy / Surface treatment / Insert metal
Research Abstract	The Al-Mg-Si series A6063 alloy reinforced with alumina short fibers has been diffusion-bonded so that the bond interface is perpendicular to the direction of fibers, and the effects of surface treatments, welding parameters and insert metals on the bond strength have been systematically investigated. The surface treatments used were (i)electropolishing,(ii)turning in a lathe and (iii)wire brushing. On the faying surface finished by (i), fibers protruded from the surface of the matrix metal were observed, and their height increased with electropolishing time. Treatment (i) resulted in bond strength considerably higher than (ii) and (iii), though the bond strength was decreased with the increase in the protruded height of fibers more than 8 <mu> m. This decrease in the bond strength was probably due to the suppression of intimate contact between matrix surfaces by protruded fibers which were broken by welding pressure and laid on the bond interface. In the case of (iii), a lot of fine fragments of the fiber broken by the wire brushing and an increase in iron content were observed at the bond interface. These fragments of the fiber and increase in iron content seem to have harmful effects on the bond strength, since (iii) resulted in the lowest bond strength. In the case of (ii), the fine fragment of the fiber was observed, but no increase in iron content could be found. The application of insert metals of Al-Cu-Mg A2017 alloy, Al-Zn-Mg A7075 alloy, copper and silver foils extended the range of welding conditions to obtain high bond strength, and decreased the welding deformation; e.g., in the case of (i), bond strength not less than the tensile strength of the base metal was obtained with small welding deformation by using the insert metals of A2017 and copper.