– In my study, I combined detailed microstructural analysis, fatigue testing, and fracture analysis to understand how fatigue cracks initiate, says Faezeh Javadzadeh Kalahroudi. I also evaluated whether near-net shape manufacturing can reduce the need for post-processing by comparing surface properties and fatigue behavior.

Modern manufacturing techniques enable the production of advanced metal components in their nearly final shape. One such technique is powder metallurgy combined with hot isostatic pressing (PM-HIP), where metal powder is compressed under high pressure and temperature. This method is used to manufacture high-performance materials for aircraft, energy systems, and tooling applications.

The study examined two PM-HIP manufactured materials: the nickel-based superalloy Inconel 625, which can withstand very high temperatures, and a high-nitrogen tool steel. The goal was to understand how microstructural features affect the materials’ lifetime under repeated loading.

Detailed microstructural characterization and extensive fatigue testing were performed to evaluate whether post-processing steps such as grinding and milling could be reduced by using near-net shape manufacturing.

The results showed that, depending on loading conditions and stress levels, defects from the PM-HIP process or microstructural features could lead to fatigue failure.

Overall, the study shows that even advanced materials are strongly influenced by small details in their internal structure. To achieve the best possible performance, the manufacturing process must therefore be carefully optimized for the intended application.

Read more here: From Powder to Performance: Microstructure-Fatigue Relationships in PM-HIPed Superalloy and Tool-Steel