The Use of High Pressure Heat Treatment for Aerospace Applications

Hot isostatic pressing (HIP) is commonly used for critical structural flight applications where vibration and fatigue loading, thermal expansion/contraction due to temperature variations, and compressive stresses require maximum material performance and reliability. This process has been used on castings, additively manufactured parts, and sintered products to increase density and eliminate defects for improved performance and reliability, with any modification or optimization of the microstructure performed in separate heat treat equipment.

Advancements in HIP equipment now offer the ability to integrate HIP and heat treatment in the HIP furnace with the aid of controllable high-speed cooling and in-HIP quenching of the highly pressurized gas media. This post-process strategy is referred to as High Pressure Heat Treatment (HPHT). HPHT has shown to not only offer improvement in productivity by eliminating heat treat processing steps, but also provides a path to prevent anomalies during heat treatment including thermally induced porosity and part quench cracking and distortion.

This presentation will cover the fundamentals of HIP. Then advancements in HIP equipment enabling the ability to combine multiple post processing steps including HIP and heat treatment will be showcased highlighting the opportunities from a productivity, producibility and performance standpoint. Then HPHT case studies will be reviewed for nickel, titanium, and aluminum base alloys used for aerospace applications. To conclude future developments of HPHT will be discussed.