Microstructures and mechanical properties of α‐SiC ceramics after high‐temperature laser shock peening

Abstract

A novel high-temperature laser shock peening (HT-LSP) process was applied to polycrystalline α-SiC to improve the mechanical performance. HT-LSP prevents microcrack formation on the surface while induces plastic deformation in the form of dislocation slip on the basal planes, which may be caused by the combination of high shock pressure and a lower critical resolved shear stress at 1000°C. A maximum compressive residual stress of 650 MPa, measured with Raman spectroscopy, was introduced into the surface of α-SiC by HT-LSP, which can increase the nanohardness and in-plane fracture toughness of α-SiC by 8% and 36%, respectively. This work presents a fundamental base for the promising applications of HT-LSP to brittle ceramics to increase their plasticity and mechanical properties.

Improvement in Bending Strength of Silicon Nitride through Laser Peening

“…However, in previous studies, change in bending strength of ceramics after LP application had not been investigated, except by Akita et al [ 11 ]. Surface damage can be prevented by applying a coating called a sacrificial layer during LP construction and, in previous studies, laser peening with coating has been widely used for ceramics [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. However, the changes in residual stress and bending strength with and without coating are also not clear.…”

Determination of the Pressure Dependence of Raman Mode for an Alumina–Glass Pair in Hertzian Contact

“…The analysis of ceramics by Raman spectroscopy offers interesting characterisation perspectives for mechanics [ 13 , 17 , 18 ] and tribology [ 16 , 19 , 20 ]. The spectrometer laser can reach micrometres or even sub-micrometre probe sizes when focused on a sample using a microscope.…”