Revealing hydrogen-induced short-range ordering (SRO) effects in high temperature materials by muon spectroscopy

As hydrogen becomes increasingly important in climate-friendly technologies, understanding its impact on high-temperature materials is essential. This study explores hydrogen-induced short-range ordering (SRO) effects in Ni-based alloys using muon spectroscopy. Such alloys are critical in hydrogen-based combustion applications, where embrittlement and other material changes pose challenges. We focus on two alloys: Ni80Cr20 (Nichrom) and Ni80Mo20, which serve as models for commercial superalloys. Hydrogen-charged samples of Nichrom at 300°C and 500°C will be compared with solution-annealed and aged references. For Ni80Mo20, solution-annealed and aged samples will also be tested, with SRO expected in the aged condition. Muon spectroscopy, sensitive to local magnetic fields and chemical ordering, will be conducted at four temperatures (50K, 100K, 150K, and 273K) to detect potential SRO effects. Initial positron annihilation results suggest SRO may occur in hydrogen-charged samples, highlighting the need for deeper investigation. This research aims to enhance understanding of hydrogen's effects on high-temperature alloys, aiding in the development of more resilient materials for industrial hydrogen applications.