New Mg-based amorphous alloys with high strength and good ductility were produced in the Mg-Ce-Ni system by melt spinning. The tensile fracture strength ( σf) and Vickers hardness reach 750 MPa and 199 DPN for Mg80Ce10Ni10. The specific strength defined by the ratio of σf to density is as high as 27, being considerably higher than the highest value (≃20) for conventional Al-based alloys. The high-strength Mg-base amorphous alloys are expected to attract much attention as a new type of high-strength material with low density.

The fillability and imprintability of a Ni-based bulk metallic glass (BMG) prepared by the precision die-casting was investigated. A threedimensional microgear made of Ni-based BMG is successfully prepared by the precision die-casting technique. The cast Ni-based BMG has excellent fillability against a microindentation formed by Vickers indentation, and the filling area obtained using a confocal scanning microscope reaches 99%. In addition, the cast Ni-based BMG exhibits excellent imprintability of the die surface even on a nanometer scale. It is therefore concluded that the Ni-based BMG is suitable as a material for micromachines due to its superior fillability and imprintability.

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Metallic foams are commonly produced using hydride foaming agents. Carbonates are safer to handle than hydrides; however, their use in the powder metallurgy (PM) route to obtaining a fine and homogenous cell structure has not been evaluated. In this study, carbonates and hydroxides were investigated as foaming agents for the production of Al-Si-Cu alloy foams by the PM route. The thermal decomposition behavior of the foaming agents was evaluated in conjunction with the cell structure of the aluminum foams produced. From the results, it was clarified that a foaming agent that began decomposing after the matrix melted is required to obtain a fine and homogenous cell structure. The TiH 2 foam formed under similar conditions was obviously different and had a coarse and rounded cell structure. MgCO 3 and CaMg(CO 3 ) 2 were selected as suitable foaming agents for the Al-Si-Cu alloy. Once expanded, the CaMg(CO 3 ) 2 foam had a specific gravity of 1.19 and a homogeneous, fine and spherical cell structure.

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