This study presents the design, preparation, and characterization of thirty new medium-entropy alloys (MEAs) in three systems: Al-Ti-Nb-Zr, Al-Ti-Nb-V, and Al-Ti-Nb-Hf. The hardness of the alloys ranged from 320 to 800 HV_0.3. Among the alloys studied, Al₁₅Ti₄₀Nb₃₀Zr₁₅ exhibited the highest-reversible hydrogen storage capacity (1.03 wt.%), with an H/M value of 0.68, comparable to LaNi₅, but with a reduced density (5.11 g·cm⁻³) and without rare earth elements. This study further reveals a strong correlation between hardness and hydrogen absorption/desorption; higher hardness is responsible for reduced hydrogen uptake. This finding highlights the interplay between a material’s properties and hydrogen storage behavior in MEAs, and has implications for the development of efficient hydrogen storage materials.

This study presents the development of a novel material for a spherical impact pad for tundishes during steel production, focusing on improving steel cleanliness and flow optimization. Traditional low-carbon and ultra-low carbon concrete (LCC/ULCC) materials are replaced with a new cement-free mixture, utilizing a sol–gel method binder. This innovative approach leads to the creation of IPC TECAST BPV CST, a refractory concrete with enhanced resistance to corrosion and shape stability under extreme conditions. The material’s effectiveness is demonstrated through operational tests, showing remarkable durability and no erosion defects after extensive use in casting liquid metal. The sol–gel binder significantly reduces the carbon footprint and energy consumption during the drying process, compared to traditional concretes. This study concludes that the new material not only withstands the dynamic environment of liquid steel but also ensures consistent dynamic flow conditions throughout the steel casting process, marking a significant advancement in tundish impact pad technology.