What Can Plasticity of Amorphous Silicon Tell Us about Plasticity of Metallic Glasses?

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 39; no. 8; pp. 1762 - 1778
• Main Authors: Argon, A.S., Demkowicz, M.J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Boston Springer US 01.08.2008; Springer
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Exact sciences and technology; Materials Science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metallic Materials; Metals. Metallurgy; Nanotechnology; Structural Materials; Surfaces and Interfaces; Symposium: Bulk Metallic Glasses IV; Thin Films; Metallic Glass; Plastic Event; Plastic Strain Increment; Plastic Relaxation; Strain Softening; Mechanical properties; Metallic glasses; Amorphous alloy; Plasticity
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-007-9368-2

In a recent set of computer simulations, we have analyzed the atomic-level kinematics and kinetics of the plastic relaxations that constitute shear transformations (STs) responsible for plasticity in amorphous silicon (a-Si). Here, we summarize the rich mechanistic details of the triggering of these transformations from “fertile” sites having a slight excess of liquidlike atomic environments and develop analytical models for the evolution of liquidlike material with plastic strain, leading to a unique flow state. Furthermore, a kinetic model of flow is developed, which accounts for the stress-strain curves with broad yield phenomena as well as for the temperature dependence of the plastic resistance found in the simulations. While the details of these findings apply specifically to network glasses of a-Si, we find far-reaching parallels to the flow mechanisms in metallic and polymeric glasses.