Deformation and Cracking in Ge–Sb–Se Chalcogenide Glasses During Indentation

Abstract

Deformation and cracking behavior of Ge–Sb–Se binary and ternary chalcogenide glasses of varying average covalent coordination number, 〈 r 〉, was studied by indenting with Vickers and Brinell microindenters using static and recording machines, and subsequent analysis using a non‐contact profilometer. Vickers‐produced cracks were the smallest around the GeSe 4 composition (〈 r 〉=2.4) after unloading, hence the indentation toughness was a maximum and the brittleness a minimum at 〈 r 〉=2.4. Brinell‐created pond (crater) depth, the mound (pile‐up) height, and the radial fractures originating from the mounds displayed minima in the binaries, presumably due to maximized elastic recovery around 〈 r 〉=2.4. Consequently, Brinell hardness computed from the unloaded depth ( H BD ) showed a maximum around GeSe 4 . The maximized elastic recovery around GeSe 4 is consistent with Phillips' optimized connectivity arguments. GeSe 4 resembles the “anomalous” SiO 2 glass for deformation and cracking behavior. Surprisingly, many of the extrema were nearly non‐existent in the ternary glasses. The apparent contrast to the binary glasses is not understood.