Individual powder particles, as well as powder particles and solid components from different material groups (PM steel/cemented carbide, PM steel/cobalt-based hard alloys and PM steel/superalloy), are bonded by solid-state diffusion during hot isostatic pressing at different temperature ranges.
After HIP, the bond between the material groups is inspected using ultrasound.
Simultaneous sintering and consolidation of the shaped components in a HIP system allow defect-free, quasi-isotropic components to be produced in a single process step. Conventional pressureless-sintered PM components, by contrast, often require forming to increase their density and improve quality. Even with the additional effort of subsequent heat treatment, traces of deformation texture may remain; these do not arise in the first place during hot isostatic pressing. Surfaces can also oxidise during forming in air, whereas this is prevented in the HIP process.