Laser additive manufacturing of ultra-high temperature Ta4HfC5 ceramic components

Ta₄HfC₅ is one of the few materials with a melting point above 4000 K, making it a promising candidate for components operating in extreme environments. However, conventional manufacturing methods for Ta₄HfC₅ are limited by high processing temperatures, restricted geometries, and complex machining requirements. In this work, we present a novel approach to fabricating dense, single-phase Ta₄HfC₅ ceramic using laser powder bed fusion (LPBF). The LPBF-processed Ta₄HfC₅ exhibits a relative density of up to 98.3 % and a face-centered cubic solid solution with a lattice constant of 4.49 Å and an average grain size of 10.5 μm. The study reveals excellent oxidation resistance, with an onset temperature of 787 °C and a DTG peak of 0.0776 %/°C at 913.58 °C. The material's thermal conductivity increases from 3.3 to 6.5 W/(m·K) between 30 °C and 1000 °C. The micropillar compressive strength is 2.4 ± 0.7 GPa, with certain grain orientations achieving up to 3.78 GPa without failure. Compared to conventionally produced Ta₄HfC₅, the LPBF-fabricated components demonstrate superior oxidation stability and mechanical performance. These results establish LPBF as a viable and energy-efficient route for manufacturing high-performance Ta₄HfC₅ components with complex geometries.