The effect of pressure application by hot isostatic press (HIP) during diffusion bonding on microstructure evolution and bonding strength was studied using a couple of an Fe-Al alloy (Fe-Al) and CrMo steel (CrMo). Columnar microstructure evolution from the joint interface to the CrMo side is suppressed and aluminum diffusion from Fe-Al to CrMo is retarded with pressure application. Refined microstructure with fine precipitates is observed in the CrMo side beyond the columnar grains of the couple bonded with pressure. The application of pressure decreases the bonding strength and the strain to failure. It is concluded that the application of pressure provides microstructure refinement and strong hardening in the CrMo side of the couple, although it is not beneficial for bonding strength.
- Diffusion bonding
- Hot isostatic pressing (HIP)
- Iron aluminum alloys
- Orientation imaging microscopy (OIM)