Evaluation of fracture toughness of small volumes by means of cube-corner nanoindentation

Abstract

In this work, the applicability of the two most commonly used equations for calculating the fracture toughness by nanoindentation is discussed in terms of the indenter geometry and the indentation crack morphology. These equations are calibrated for Berkovich and cube-corner indenters taking into account the actual indentation crack morphology, aimed at attaining a more reliable estimation of fracture toughness in small material volumes by nanoindentation. Hill's expanding cavity solution for an elastic-plastic solid and assuming a half-penny crack configuration, suggested the following expression to calculate K IC [5]:

New insights into nanoindentation crack initiation in ion‐exchanged sodium aluminosilicate glass

“…Despite having the CS greater than 380 MPa in all ion‐exchanged glasses used in this study (Figure ), the threshold load was still lower than that of the raw glass. According to previous researchers, the discrepancy between our results with the previous works come from the different residual stress field between the Vickers and the cube‐corner indenter caused by the different centerline‐to‐face angle between the two indenters.…”

“…where l is the length of the crack from the indentation corner, a is the length from the central point of the indentation impression to the indentation corner, and v is a semiempirical stress-field amplitude. For a Vickers indenter, v=0.015, 44 and for a cube-corner indenter used here, v=0.057. 44,45 Thus, the v, which is related to the radial crack driving force, 11 of the cube-corner indenter is approximately quadruple the same parameter of the Vickers indenter.…”

“…For a Vickers indenter, v=0.015, 44 and for a cube-corner indenter used here, v=0.057. 44,45 Thus, the v, which is related to the radial crack driving force, 11 of the cube-corner indenter is approximately quadruple the same parameter of the Vickers indenter. As a result, for a cube-corner indenter, a higher CS is needed to resist the increased crack driving force.…”

Hydrogen-induced microstructure, texture and mechanical property evolutions in a high-pressure torsion processed zirconium alloy

“…3a). Such indentation crack development is driven by the residual stress field in the material, and the crack extending length is related to the material crack propagation resistance [19]. The fracture toughness K IC of e-hydride can be estimated following the indentation microfracture method and using the expression [19,20]:…”

Микротвердость И Трещиностойкость Оксида Галлия

“…Слои α-и β-Ga 2 O 3 были получены в реакторе хлоридной эпитаксии, разработанном для этих процессов ООО " Совершенные кристаллы" [13,14]. Объемные кристаллы были двух типов: коммерческая пластина β- Существует большое число работ [17][18][19][20][21], в которых рассматривается и обосновывается подход к определению K 1C в опытах по микротвердости. В [17] уточнено значение коэффициента пропорциональности 0.016, после чего выражение для определения K 1C приобрело следующий вид:…”