Elastic–plastic transition during nanoindentation in bulk GaN crystal

Yield shear stress dependence on nanoindentation strain rate in bulk GaN crystal

“…In order to obtain the critical load P crit dependence on strain rate, the indentation velocity v was ranged from 0.16 nm/s to 800 nm/s with constant temperature T = 300 K. Young's modulus E, hardness H and maximum shear stress τ max were calculated by following the Ref. [3,4].…”

“…The most articles in the past studies have investigated the mechanical properties of multilayered GaN crystals on the sapphire substrate [3] and there are a few articles which investigated that of bulk GaN crystals [4], because these bulk GaN crystals were developed quite recent years and they are still scarce materials now. We selected bulk GaN crystals for current study in order to determine the precise mechanical responses, and we applied the nanoindentation technique which is increasingly serving a significant role of revealing the material physical properties in recent years [5][6][7][8][9][10][11][12][13].…”

Mechanical properties characterization of c ‐plane (0001) and m ‐plane (10–10) GaN by nanoindentation examination

“…The detail calculation procedure for the indenter curvature radius was described in Ref. [13,14]. Penetration depth h was registered with using each indenter, while the load P applied up to P max was equal to 5 mN (0.51 gf) or 9 mN (0.92 gf).…”

Mechanical responses of single-crystal ZnO

“…Although nanoindentation has been proven as a powerful technique in obtaining critical information on mechanical properties (hardness and elastic modulus) of the investigated materials through the detailed analyses of the load-displacement curves [4][5][6][7][8], the modifications of the obtained mechanical properties associated with contact-induced deformation (or damages) and related dislocation generation and propagation mechanisms are, however, only accessible by other independent methods. To this * Tel.…”