Isochemical control over structural state and mechanical properties in Pd-based metallic glass by sputter deposition at elevated temperatures

Daniel J Magagnosc,Le Yu,Gang Feng,Xuemei Cheng,Daniel S Gianola

doi:10.1063/1.4960388

Abstract

Sputter deposition, while varying the substrate temperature, is employed to isochemically control the structural state and concomitant mechanical response in a Pd-based metallic glass at the time of glass formation. Increasing the deposition temperature from 333 K to 461 K results in a 33.5% increase in hardness to 9.69 GPa for amorphous films. Further increasing the temperature leads to a decrease in hardness, indicating low and high temperature deposition regimes where increased surface mobility allows access to a more relaxed and more rejuvenated structure, respectively. Through this mechanism we access the range of achievable structural states, from ultrastable to highly liquid-like glasses.

Highlights

Isochemical control over structural state and mechanical properties in Pd-based metallic glass by sputter deposition at elevated temperatures
Further increasing the temperature leads to a decrease in hardness, indicating low and high temperature deposition regimes where increased surface mobility allows access to a more relaxed and more rejuvenated structure, respectively
Relaxed structures exhibit lower excess enthalpies[4] and increased hardness and modulus;[21,22] rejuvenated structures have large excess enthalpies and show lower hardness and modulus.[23]. While this conceptual framework provides a simple mapping of the glass structural state on a reduced energy spectrum, the details of the potential energy landscape (PEL), such as the mega-basin profile as well as the density and organization of inherent states, define the aEmail: gianola@engr.ucsb.edu 2166-532X/2016/4(8)/086104/8

Summary

Introduction

Isochemical control over structural state and mechanical properties in Pd-based metallic glass by sputter deposition at elevated temperatures. (Received 13 June 2016; accepted 19 July 2016; published online 8 August 2016)

Results

Conclusion