Microstructural mechanisms of tuning the deformation behaviors in annealed metallic glasses

• Published in: Journal of alloys and compounds Vol. 876; p. 160029
• Main Authors: Li, Ming-fei, Wang, Da-peng, Malomo, Babafemi, Yang, Liang
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25.09.2021; Elsevier BV
• Subjects: Amorphous materials; Annealing; Coupling (molecular); Deformation; Deformation effects; Edge dislocations; Free volume; Metallic glass; Metallic glasses; Microstructure; Molecular dynamics; Shear bands; Synchrotron radiation; Synchrotrons; Tuning; Free volume; Molecular dynamics; Deformation; Microstructure; Metallic glass
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.160029

•Essential mechanisms of deformation in annealed fully amorphous alloys was studied.•Higher annealing temperature leads to higher yield strength and poor plasticity.•The deformation behavior is tuned by free volumes, clusters and atomic packing.•Structural changes influence formation of shear transition zones and shear bands. [Display omitted] An insightful investigation on the deformation behavior of annealed metallic glass (MG) has been conducted in this study to uncover the essential mechanisms of deformation in annealed MGs that remain fully amorphous, a subject that is complex and challenging to the MG scientific community. By coupling synchrotron radiation-based experiments with a series of molecular dynamics simulations and calculations, representative microstructure models of deformed MGs in as-prepared and annealed conditions were successfully probed. It was discovered that higher maximum strength and poor plasticity of the annealed MGs are manifestations of the causative effect of higher temperatures from the annealing treatment. The deformation behavior was tuned by microstructural parameters, in terms of fraction of free volumes (FFVs), clusters and atomic packing efficiencies (APEs) to classify the evolution phenomena. The observed variations of APE and FFV values underscored the distinctions in the deformation behavior of the MG models. However, annealing-induced structural changes significantly influenced the initiation and propagation of shear transition zones, formation of shear bands and the overall deformation behavior with a beneficial strengthening effect. In totality, this work has provided compelling results to demystify the intricacies associated with the microstructural tuning of deformation behavior in annealed MGs.