The pressure welding process involves the simultaneous application of pressing forces and high temperatures. The components to be joined are heated to the required temperature under high-vacuum. The pressing forces are then applied by the ram (uniaxially). This helps smooth the rough peaks of the material surfaces thus establishing close material contact between the mating surfaces. In contrast to many other welding processes, diffusion bonding does without a liquid phase and external materials.
The join is formed by the transfer of material across the interfaces. Since the diffusion rates are strongly temperature-dependent, the joining process is performed at approx. 50% to 90% of the melting temperature of the materials to be joined.
With holding times of sufficient duration, diffusion processes that coincide with grain growth cause residual pores in the joint to close, ideally resulting in the complete “healing” of the joint seam. The result is a monolithic component with no discernible joint (microscopic and macroscopic).
Individual factors such as the pressing force and the holding time at working temperature can vary strongly from material to material and therefore require comprehensive metallurgic expertise when it comes to deriving the appropriate process parameters. Get in touch with us, and we can advise you in detail and identify the process that’s right for you in our Innovation Lab.