Effect of microstructural coarsening on Hertzian contact damage in silicon nitride

Effect of temperature on the pre-creep mechanical properties of silicon nitride

“…These constitutive equations are based on a critical shear condition for yield but incorporating a strain-hardening characteristic to allow for local elastic constraints on the sliding shear faults that are responsible for quasi-plasticity in ceramic materials. 6,18,[22][23][24] These uniaxial equations are then generalized to multiaxial behavior using the von Mises yield criterion. The application of this type of treatment, typically used in metallic materials, to quasi-plastic ceramics has been justified by Fischer-Cripps and Lawn, 25,26 and proved to be useful for predicting the main features of Hertzian stress-strain curves and the evolving deformation zone geometries, despite the fact that the underlying deformation mechanism is shear faulting instead of dislocation sliding.…”

Quasi-Plastic Deformation of WC-Co Composites Loaded with a Spherical Indenter

“…[17] Recent studies using Hertzian indentation with spherical indenters have demonstrated that plasticity is attainable in ceramics with certain heterogeneous microstructures. [18][19][20][21][22][23] Considering that WC-Co materials possess mechanical characteristics in between metallic alloys and ceramic composites, the Hertzian contact methodology may be seen as a useful tool to gain insights into their mechanical behaviors. In the past, the indentation technique has indeed been used to study WC-Co materials.…”

Interphase Debonding in High Temperature Ceramic Composites

“…It has also been demonstrated to occur in some ceramics at Hertzian contacts, e.g. in alumina (Guiberteau et al, 1993;Guiberteau et al, 1994;Wei and Lawn, 1996) and silicon nitride (Xu et al, 1995). In such cases, the fault dimension c increases progressively with loading, and in some cases also with unloading (Padture and Lawn, 1995a, b), further reducing the effective modulus.…”

“…These shear faults may be twins [e.g. alumina (Guiberteau et al, 1993(Guiberteau et al, ,1994Wei and Lawn, 1996), silicon nitride (Xu et al, 1995)], or weak grain or interphase boundaries [platelet or needle structures, e.g. in-situ toughened silicon carbide Padture and Lawn, 1995a, b),,silicon nitride (Xu et al, 1995), glass-ceramics (Caie/ al., 1994a, b), and particlereinforced alumina composites ].…”