Mechanically alloyed multi-component Mo-based amorphous alloys with wide supercooled liquid region

A Mo44Si26Ta5Zr5Fe3Co12Y5 multi-component amorphous alloy was developed via mechanically alloying (MA), It exhibits a record high glass transition temperature of 1202 K and crystallization temperature of 1324 K, an ultrahigh hardness of 18 GPa, as well as a wide supercooled liquid region (122 K) promising for processing through powder metallurgy routes. Here we present the details of the phase evolution during MA and discuss the effects of alloying elements, starting from the Mo-Co and Mo-Si binary systems, through two series of ternary alloys, eventually reaching the desired properties by selecting additional components. The propensity for glass formation and the high thermal stability were interpreted in terms of the negative heat of mixing of the elements introduced, as well as a uniform coverage spanning a wide range of atomic sizes. (c) 2006 Elsevier B.V. All rights reserved.