A connection between the structural alpha-relaxation and the beta-relaxation found in bulk metallic glass-formers

摘要

New metallic glasses containing La or Ce have been introduced that havedynamic properties bordering on extremes of conventional metallic glasses. Thisprovides opportunity to test trends or correlations established before inmolecular and polymeric glass-formers if exist the same exist in the broaderfamily of metallic glasses. Due to the drastically different chemical andphysical structure of metallic glass-formers than soft matter, there is noguarantee that any correlation found in the latter will hold in the former. Iffound, the result brings metallic glasses closer to the much wider classes ofglass-formers by the similarity in properties, and possibly have the sameexplanation. In non-metallic glass-formers, a general and fundamentalconnection has been established between the non-exponentiality parameter of thestructural alpha-relaxation and the separation between its relaxation time andthe beta-relaxation time. In this paper we explore the experimental data ofmetallic glass-formers and show the correlation applies. An explanation of thiscorrelation is given. The establishment of the correlation may facilitate theunderstanding of the roles played by the beta-relaxation observed inmacroscopic properties of metallic glasses including the relations to sheartransformation zone, ductile-brittle transition in deformation,crystallization, and diffusion.