Thermal stability of mechanically alloyed nitride/amorphous Zr65Al7.5Cu17.5Ni10 alloy composites

Elemental powder mixtures with a composition of Zr65Al7:5Cu17:5Ni10 together with 10 vol.% AlN,Si 3N4 and TiN particles were mechanically alloyed to form nitride/amorphous alloy matrix composites. The microstructure of ballmilled products was characterized using X-ray diffraction and transmission electron microscopy. Glass transition and crystallization kinetics of the nitride-containing composites were investigated with differential scanning calorimetry. In the final products of ball milling,initial particles of crystallite nitride were refined to a nanoscale and homogeneously dispersed in the amorphous Zr-based alloy matrix to form the composites. The nitride-containing composites exhibit a larger supercooled liquid region DTx compared with the amorphous Zr-based alloy without nitrides. The isothermal crystallization kinetics of the mechanically alloyed amorphous Zr65Al7:5Cu17:5Ni10 alloy with or without nitride does not follow the conventional Johnson–Mehl–Avrami model. 2002 Elsevier Science B.V. All rights reserved.