Non-isothermal austenitic transformation kinetics in Fe–10Cr–1Co alloy

Differential thermal analysis (DTA) has been employed to study the kinetics of the matensite ( α^' ) → austenite ( γ ) transformation for ternary Fe–10Cr–1Co alloy upon heating to 1373 K (austenitization). An austenitic transformation model, based on assumption of continuous nucleation, diffusion-controlled growth and incorporating consideration of an impingement correction, has been introduced to investigate the influence of heating rate on the austenitic transformation behaviors. The grain distribution percentage subjected to heating with different rates is more uniform with the increase in heating rate, and the obtained average grain diameter is smaller. The temperature of austenitic transformation increases with increasing heating rate due to a larger overheating. The growth activation energy showing a negative value indicates the growth of austenite particle is a spontaneous reaction, and the nucleation activation energy decreases with the increase in heating rate due to larger overheating, and thus austenitic transformation in Fe–10Cr–1Co alloy can be considered as a nucleation-controlled process.