Metallic glasses: past and future...


Профессор Акихиса Иноуэ

Novel materials can drastically change our human life style as exemplified for steels developed around 1850 and plastic synthesized in 1947. When we focus on metallic materials, it is well known that all metallic alloys, which have been used for several thousand years, consist of a crystalline structure with three-dimensional long periodic atomic configuration. In such a situation, novel bulk metallic materials without periodic atomic configuration on a long range scale were synthesized for the first time by copper mold casting process in 1989 and has been named as bulk metallic glasses. The bulk metallic glasses have been formed in a variety of alloy systems by various casting processes in a bulk form with a thickness up to 80 mm and exhibit various unique characteristics due to the liquid-like nonperiodic structure. As unique characteristics which cannot be obtained for conventional crystalline metallic alloys, one can list up high strength, low Young’s modulus, large elastic strain, high fatigue strength, high fracture toughness, high corrosion resistance, high wear resistance, low friction coefficient, low solidification shrinkage ratio, good precise castability, good nanoinprintability, high surface smoothness, high reflection ratio, lower melting temperature, easy homogeneous mixed liquid etc. By utilizing the simultaneous achievement of their characteristics, bulk metallic glasses have been used in our human life and their total sailing money is estimated to reach as large as about 20 billion US dollars in 2016.