Thermal shock-induced fracture of ion-implanted LiF crystals

Abstract

Monocrystals of LiF, ion implanted with Ar+, were exposed to thermal shock in a plasma of different intensities. Ion implantation substantially alters the fracture pattern and characteristics of the material, particularly in reducing the thermal shock resistance parameter, S′, and in increasing the damage resistance parameter, S″. The former parameter indicates that ion implantation allows fracture to be initiated at lower thermal shock temperature differences and the latter parameter is associated with higher crack densities and lower crack penetration depths. The increase in the parameter S″ indicates that ion implantation can result in a higher mechanical stability and greater durability of the crystals damaged by thermal shock. Surface melting at very high heat fluxes eliminates any effect of ion implantation.