Interdependence between glass stability and phase formation sequence during crystallization of Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass

Abstract

Abstract Knowledge of the crystallization sequence of metallic glasses can yield a deep insight into the origin of their thermal stability. Crystallization of metallic glasses often leads to the simultaneous formation of different metastable crystalline phases that makes their identification difficult. In order to separate formation of crystalline phases from each other, long term isothermal pre-annealing below the glass transition temperature of Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk metallic glass prior to crystallization was performed. It is found that this pre-annealing strongly influences the crystallization sequence and depending on the pre-annealing time leads to preferential formation of different phases. In addition to the well known intermetallic Be2Zr phase and a quasicrystalline phase, three further previously unknown crystalline phases are identified and described in terms of their structure and composition. The formation of the crystalline phases is discussed with respect to the glass forming ability and thermal stability of the glass phase.