In this work, Ti43.3Zr21.7Ni7.5Be27.5 (at.%) bulk metallic glass and Zr76.11Ti4.20Cu4.51Ni3.16Be1.49Nb10.53 (at.%) bulk metallic glass composite are used to butt-weld identical alloy specimens using a fiber laser beam under a vacuum. Thereafter, various tests are conducted on the welded specimens to evaluate the applicability of the laser welding process to bulk metallic glasses and bulk metallic glass composites. Crystallization is suppressed during the welding process as much as possible, and welded Ti-based bulk metallic glass and Zr-based bulk metallic glass composite exhibit their original properties although some crystalline phases are formed in the welding fusion zone in Ti-based bulk metallic glass. Therefore, laser welding under a vacuum is appraised as a feasible technology to join bulk metallic glasses and bulk metallic glass composites.

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In case of the uranium (U) and zirconium (Zr) powders which have been utilized for the production of a metallic fuel in the various nuclear applications, the homogenous distribution of U powders in the Zr-U pellet has influenced significantly on the nuclear fuel performance. The inhomogeneity in a powder process was changed by various intricate factors, e.g. powder size, shape, distribution and so on. Particularly, the U inhomogeneity in the Zr-U pellets occurs by segregation derived from the great gaps of densities between Zr and U during compaction of the mixed powders. In this study, the relationship between powder size and homogeneity was investigated by using the different-sized U powders. The microstructure in Zr-U pellets reveals more homogeneity when the weight ration of Zr and U powders are close to 1. In addition, homogeneous pellets which were produced by fine U powders have higher density because the homogeneity affects the alloying reaction during sintering and the densification behavior of pore induced by powder size.