EFFECT OF SPECIMEN THICKNESS ON THE IMPACT RESISTANCE OF ALUMINA

During the course of an ongoing study into the impact and erosion prop erties of alumina by the US Bureau of Mines, it was discovered that sp ecimen thickness had a significant effect upon certain fractographic o bservations. To quantify this effect, impact studies were carried out on 1.9, 3.1 and 10.0 mm thick Al2O3 (alumina) discs. These discs were impacted at velocities from 15 to 65 m s(-1) using 1.69 mm-diameter WC -Co spheres. In conjunction with this experimental approach, finite el ement models of the impact couples were constructed for the 1.9 and 10 .0 mm-thick alumina discs. An elastic/plastic analysis was performed o f the impact event in each case. Experimental and numerical results in dicate that the length, depth and geometry of radial cracks are strong ly dependent upon specimen thickness.