Liquid Impact Erosion of Single-Crystal and Coated Materials

摘要

Lithium fluoride in its single-crystal form is an interesting material for investigating the development of fracture by multiple liquid impact owing to its well-characterised crystal structure. The development of fracture during liquid impact is attributed to the extension of short circumferential cracks produced around the loaded area by the passing Rayleigh stress wave after the impact event. The damage threshold of single-crystal lithium fluoride is developed using the multiple impact jet apparatus (M.I.J.A.) as a result of identifying the characteristic fracture annulus associated with liquid impact during a controlled experimental procedure. The observation of damage produced in solids by liquid impact has practical significance in the problems associated with supersonic aircraft flying through rain and in the erosion of turbine blades. The addition of coatings to the surface provides a form of protection at higher speeds but may not completely inhibit damage.