극한 환경용 합금 설계 및 공정 연구실

to develop advanced processing technology, as well as the chemical, microstructural, and mechanical characterization. High/Medium-Entropy Alloys (H/MEAs) represent a new paradigm in alloy design by mixing multiple principal elements in high proportions. These alloys exhibit outstanding mechanical and functional properties, surpassing the limitations of conventional alloys. We design the novel alloys possessing both ultra-high strength and remarkable ductility by harnessing the severe lattice distortion of H/MEAs. we performed DFT calculations to evaluate the phase stability and the generalized stacking fault energy (GSFE) of each precipitate phase. These analyses allowed us to clarify the effects of precipitates on both phase formation and deformation behavior. We investigate martensitic microstructures, focusing on reorientation behavior of martensite variants and their deformation mechanisms. By integrating microstructural control with tailored alloying strategies, we aim to enhance both mechanical strength and toughenss, while also seeking mechanisms to control anisotropic thermal expansion behavior. We examine hydrogen embrittlement (HE) and cathodic corrosion resistance in crossover Al-Zn-Mg alloys with Zn/Mg ratios. Electrochemical hydrogen charging and ex-situ tensile tests were conducted, and the results revealed that η′ and T′ precipitates in both the matrix and grain boundaries act as reversible hydrogen traps. Consequently, decreasing the Zn/Mg ratio reduces resistance to cathodic corrosion and HE, highlighting the importance of optimizing Zn/Mg ratios to develop hydrogen-resistant Al alloys with improved durability. We design advanced ultra-high strength steels (UHSS) with martensitic-based microstructures to optimize the combination of strength–ductility. O