Effects of heat treatment on crystallization behavior, microstructure and the resulting microhardness of a (Fe0.9Ni0.1)77Mo5P9C7.5B1.5 bulk metallic glass composite

• (Fe0.9Ni0.1)77Mo5P9C7.5B1.5 alloy shows liquid phase separation during solidification and possess composite structure.
• Both separated and matrix phases have high glass forming ability and show amorphous structure in the as‐cast state. Each phase has different composition and so possesses different crystallization temperature and hardness.
• Hardness of separated phase lower and hardness of matrix increase during the annealing at first and second crystallization temperature.

The influence of heat treatments on crystallization behavior, microstructure and the resulting microhardness of an as-quenched (Fe0.9Ni0.1)77Mo5P9C7.5B1.5 bulk metallic glass (BMG) composite was investigated. (Fe0.9Ni0.1)77Mo5P9C7.5B1.5 alloy shows liquid phase separation (LPHS) during solidification and possesses amorphous composite structure in as cast state. Amorphous composite was annealed at different temperatures as Tp1 (725 K) and Tp2 (772 K) by DSC, and effect of crystallization of the amorphous composite on hardness was investigated by XRD, SEM, EDS, DSC and micro-hardness test. In the present study, an attempt has been made to gain knowledge of the crystallization sequence of each separated phase and the effect of their crystallization on the microhardness of (Fe0.9Ni0.1)77Mo5P9C7.5B1.5 alloy. The first peak (TX1, 725 K) is attributed to the primary crystallization of the separated phases while the second one (TX2, 755 K) is ascribed to the crystallization of the amorphous matrix. Annealing at first and second crystallization peaks reduces hardness of separated phases and increases hardness of the matrix phase.