2015 Volume 56 Issue 10 Pages 1683-1687
Fixture composed of 304 stainless steel (SUS304) and 440C stainless steel (SUS440C) was employed for inducing the thermal stress to 316L stainless steel and oxygen free copper (SUS316L/OFC) cylinders to achieve diffusion bonding. For comparison, the same combination was bonded using the conventional diffusion bonding method, i.e. heating in vacuum under constant pressure. Although the thermal stress-based diffusion bonding is conducted in charcoal-reformed air, the bonding starts from 673 K. This temperature is relatively low as compared with the conventional method (873 K). Furthermore, the joint fabricated using the thermal stress-based method exhibits higher joint efficiency than one prepared using the conventional method. The highest tensile strength is attained at 1073 K and comparable to one of OFC. The bonding deformation of the thermal stress-based method is smaller than with the conventional method, since the fixture does not apply excess pressure to the diffusion couple. Thus the thermal stress-based diffusion bonding method is a promising and may be superior to the conventional method from view points of simplicity and bondability.