Figure 4: Classification of BMG formers based on Tf− Tfc values.
From: Critical fictive temperature for plasticity in metallic glasses
(a) Type I metallic glasses (Tf−Tfc<0) exhibit an embrittlement nose time shorter than the crystallization nose. As a result, these BMG formers are typically brittle but can be made ductile if a cooling rate higher than Re is applied. (b) For type II metallic glasses (Tf−Tfc>0), the embrittlement nose time is longer than the crystallization nose time; therefore, these BMG formers are always ductile. In both cases, variation of Tf with cooling rate is shown. For practical convenience, calorimetric Tg can be used to approximate Tf.
