Introducing a strain-hardening capability to improve the ductility of bulk metallic glasses via severe plastic deformation

• Published in: Acta materialia Vol. 60; no. 1; pp. 253 - 260
• Main Authors: Wang, Y.B., Qu, D.D., Wang, X.H., Cao, Y., Liao, X.Z., Kawasaki, M., Ringer, S.P., Shan, Z.W., Langdon, T.G., Shen, J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 2012; Elsevier
• Subjects: Amorphous materials; Applied sciences; Bulk metallic glasses; Ductility; Exact sciences and technology; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metallic glasses; Metals. Metallurgy; Nanocomposites; Nanostructure; Plastic deformation; Severe plastic deformation; Shear localization; Strain hardening; Transmission electron microscopy; Severe plastic deformation; Transmission electron microscopy; Ductility; Bulk metallic glasses; Metallic glasses; Mechanical properties; Amorphous alloy; Plastic deformation; Strain hardening
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2011.09.026

The great technological potential for bulk metallic glasses (BMGs) arises primarily because of their superior mechanical properties. To realize this potential, it is essential to overcome the severe ductility limitations of BMGs which are generally attributed to shear localization and strain softening. Despite much international effort, progress in improving the ductility of BMGs has been limited to certain alloys with specific compositions. Here, we report that severe plastic deformation of a quasi-constrained volume, which prevents brittle materials from fracture during the plastic deformation, can be used to induce strain hardening and to reduce shear localization in BMGs, thereby giving a significant enhancement in their ductility. Structural characterizations reveal the increased free volume and nanoscale heterogeneity induced by severe plastic deformation are responsible for the improved ductility. This finding opens a new and important pathway towards enhanced ductility of BMGs.