CRYSTALLIZATION TEMPERATURE AND HARDNESS OF NEW TYPE COBALT-BASED AMORPHOUS ALLOYS.

Abstract

Amorphous alloys with excellent thermal stability and hardness have been found in extensive composition ranges in the alloy systems of cobalt-VIb group transition metals-carbon such as Co-Cr-C, Co-Mo-C, Co-W-C, Co-Cr-Mo-C, Co-Cr-W-C, Co-Mo-W-C and Co-Cr-Mo-W-C by a rapid quenching technique. Vickers hardness of these alloys increases with increase of chromium, molybdenum and tungsten and its maximum attains about 1450 DPN. The amorphous structure is thermally more stable compared with other cobalt-based amorphous alloys. The highest crystallization temperature is 1042 K. The effectiveness of alloying elements on the increase in hardness and crystallization temperature becomes large in the order chromium, molybdenum and tungsten.