Temperature dependence of mechanical properties and defect formation mechanisms in 3C-SiC: A molecular dynamics study

• Published in: Computational materials science Vol. 227; p. 112281
• Main Authors: Nishimura, Kenji, Saitoh, Ken-ichi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2023
• Subjects: Dislocation; Molecular dynamics; Nanoindentation; Plastic deformation; Silicon carbide; Stacking fault; Molecular dynamics; Stacking fault; Silicon carbide; Plastic deformation; Nanoindentation; Dislocation
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2023.112281

[Display omitted] •Crystal defects formed under indenter are perfect dislocations at low temperature.•At high temperature dissociated Shockley partials with stacking faults appear.•Ductile behavior on (111) indent is more affected by temperature than that of (001)•Elastic response is almost independent of temperature. Nanoindentation simulations of single-crystalline cubic silicon carbide across a temperature range of 300–2000 K are performed using molecular dynamics to elucidate the temperature dependence of mechanical characteristics and lattice defect formation mechanisms. The load–displacement curves obtained by our simulations indicate weak temperature dependence of elastic responses and strong temperature dependence of plastic deformation. We reveal that the critical mean contact pressure, which is a criterion for the plasticity onset decreases with temperature. Meanwhile, plastic deformation at low temperatures starts with the nucleation and expansion of perfect dislocations, whereas the perfect dislocations dissociate into Shockley partial dislocations with stacking faults at high temperatures. After unloading, symmetric impression patterns caused by atomic arrangements on surfaces are observed at 300 K, whereas atomic pile-ups closely related to dislocation movement are formed around impressions at 2000 K. Additionally, the ductile behavior on a (111) surface indent is more affected by temperature than that on a (001) surface.