Abstract

In this research hardness variations before and after heat treatment in Fe55Cr18Mo7B16C4 amorphous alloy were evaluated using microhardness device equipped by microprocessor. Amorphous ribbons were produced from ingot casting by melt spinning method. Crystallization temperature for heat treatment of samples was determined by differential scanning calorimetric (DSC) test. Results showed there was a two-step crystallization process including first and second step crystallization. There were chosen two temperatures above first step of Crystallization (T1) and second Step of (T2). Heat treatment of ribbons were done in vacuum furnace isothermally including two treatments in T1 and T2 for 3 hours separately (Single step) and a two-steps treatment (annealing in T1 for 3 hours and then increasing temperature to T2 and annealing in this temperature for 3 hours). The hardness of all samples (before and after heat treatment) was measured. Result showed that, the hardness of ingot casting was 610 HV while the hardness of amorphous ribbon before heat treatment was about 1170 HV and reached to above 1450 HV for all heat treated samples. Result showed proper heat treatment for receiving to highest hardness is one-step treatment after second step of crystallization.