A new glass-forming ability criterion for bulk metallic glasses

A new indicator of glass-forming ability (GFA) for bulk metallic glasses (BMGs) is proposed based on crystallization processes during cooling and reheating of the supercooled liquid. The interrelationship between this new parameter and the critical cooling rate or critical section thickness is elaborated and discussed in comparison with two other representatives, i.e. reduced glass transition temperature T_rg ( = T_g/T_l, where T_g and T_l are the glass transition temperature and liquidus temperature, respectively) and supercooled liquid range ΔT_xg ( = T_x - T_g, where T_x is the onset crystallization temperature and T_g the glass transition temperature). Our results have shown that ΔT_xg alone cannot infer relative GFA for BMGs while the new parameter γ, defined as T_x/(T_g + T_l), has a much better interrelationship with GFA than T_rg. An approximation of the critical cooling rate and critical section thickness for glass formation in bulk metallic glasses is also formulated and evaluated. © 2002 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc.