Diffusion Bonding of Ferrous Alloys and their Characterization

Abstract

Diffusion bonding is a solid-state joining technique that fuses two materials together by applying pressure and heat. The atoms from one material diffuse into the other as a result of the high pressure and temperature, joining the two materials together. The diffused atoms form bond interface. Diffusion bonding is a desirable option for applications that call for high strength, because the bond formed is extremely durable and resistant to fracture. Plates of High Strength Low Alloy Steel (HSLA) were successfully bonded by diffusion bonding process with interlayer of Beryllium Copper between them. Beryllium copper alloys produces a bond that is both strong and thermally stable, which makes it suitable for high-temperature applications. Research on diffusion bonding is being done to optimize the diffusion bonding variables to achieve maximum tensile strengths. The strength was achieved at temperatures, 750°C, 800°C and 850°C for hold time 1hr 2hr and 3hr under the pressure of 20Mpa. Prior to the bonding process, the materials need to be cleaned and properly prepared in order to achieve successful diffusion bonding. This involves eliminating any contaminants and surface flaws that might adversely affect the bond. In this study samples were first cleaned by ethanol in ultrasonic cleaner for 30 minutes, secondly the samples are grinded on different emery papers ranging from p240, p600, p800, p1000, p1500, p2000 to achieve smooth even surface. Diffusion bond interface has been analyzed by scanning electron microscopy (SEM) to check the interface of joined plates. X-Ray diffraction (XRD) technique is used to determine the internal stresses.