Tungsten-Based Metallic Glasses with High Crystallization Temperature, High Modulus and High Hardness

Abstract

Ternary and quaternary tungsten-based alloys were melt-spun to produce metallic glasses having high crystallization temperature and high hardness. Alloy compositions were selected based on eutectic compositions of tungsten-based binary alloys; they are W 4 6 Ru 3 7 B 1 7 , W 5 4 Rh 2 6 B 2 0 , W 5 6 Ir 2 3 B 2 1 , etc. In most of the alloys, ductile metallic glasses were produced. DSC measurements showed that most of the metallic glasses undergo a two-step crystallization with the onset temperature of the first crystallization being as high as 1049∼1298 K. Vickers hardness values at room temperature are 13∼17 GPa. The ratio of the hardness H v to Young's modulus E satisfies the general rule for metallic glasses, i.e. H v /E 0.06. High temperature hardness measurements for W 4 6 Ru 3 7 B 1 7 and W 4 5 Re 2 3 Ru 1 5 B 1 7 metallic glasses showed that the Vickers hardness values are higher than lOGPa up to 900 K.