Hot isostatic pressing
Hot isostatic pressing (HIP) is a form of heat treatment that uses high pressure to improve material properties. That pressure is applied by an inert gas, usually argon. Time at elevated temperature and pressure allows plastic deformation, creep and diffusion to occur. Castings for critical applications are HIPed to eliminate internal porosity thereby improving mechanical properties by removing defects. HIP also enables the bonding, or cladding, of two or more materials together, either in the solid or powder form.
HIP is an important tool in powder metallurgy as well. It is used to convert powder in the solid state to fully dense components, resulting in better physical properties than those achieved by traditional melting or press and sinter manufacturing technologies. Powder can be encapsulated in shaped sheet metal and HIPed to produce near-net shape parts.