HIP does not simply “compact” the parts. In an inert atmosphere at high temperature and pressure, the closure of internal pores is usually accomplished by a combination of plastic yielding, power law creep, and diffusion mechanisms. Under different materials, pore morphologies and heat treatment conditions, the dominance of the three mechanisms is not the same.
At lower temperature but sufficient pressure, local stress around a pore may exceed the material’s yield strength. Plastic flow then occurs at the pore wall, rapidly reducing pore volume. As temperature increases, high-temperature creep becomes more active, and pore closure is governed by time, stress, and temperature rather than instantaneous yielding alone. For small pores and defects near grain boundaries, diffusion further promotes pore-wall bonding and microstructural homogenization.
The HIP diagram is commonly used in engineering to form a combination of pressure, temperature and time, which is used to determine whether a material can complete densification within the target window while avoiding abnormal grain growth, uncontrolled phase change or subsequent heat treatment conflicts. When purchasing equipment, look not just at maximum pressure and maximum temperature, but also at hot zone uniformity, heating and cooling capabilities, atmosphere cleanliness, data recording and cooling paths to support a complete window of the target material.
The content on this page is used to establish the assessment framework. Specific process parameters still need to be confirmed through sample verification based on material grade, manufacturing route, defect type, detection method and customer standards.