Abstract

In fields such as energy, nuclear power, space environment, radiation medicine, and nuclear fusion, radiation degrades materials and devices, so it is expected to develop materials with high durability and excellent functionality. In this study materials developing and the designing are mainly reviewed. It has been found that the number of defective clusters (nano-size) formed in materials by radiation above room temperature does not exceed an order of 1023m-3, and materials with high number density nanoclusters or with nano- or sub-nano- structures before irradiation are expected to exhibit high irradiation resistance. On the other hand, High-Entropy (HE) alloys, which have recently attracted much attention, have been found to have both high strength and excellent ductility, and high irradiation resistance has been reported in these alloys, presumably due to lattice distortions that can significantly affect the diffusion process of point defects. In order to gain a better understanding of the phenomena in such complex materials, it is important to develop various sophisticated measurement methods and theoretical analysis methods. In particular, it is important to improve measurement methods such as electrical resistance measurement and positron annihilation lifetime measurement, which use the fundamental properties of elementary particles, in order to measure changes at a level smaller than the nano range. In addition, it is important to develop a new measurement system that can measure changes in the nano- and micro-defect state inside such materials even under radiation, and we also introduce a challenging attempt

Keywords: Electrical resistance; Positron annihilation lifetime; Radiation; Nanocluster; High entropy alloy; Irradiation damage; Ti alloy; W; Strength; Ductility; Innovative materials