MSE Seminar Series: George Quinn
Friday, April 11, 2014
1:00 p.m.-2:00 p.m.
Room 2110 Chemical and Nuclear Engineering Building
301 405 5240
On the Edge Chipping Resistance of Brittle Materials
American Dental Association Foundation
Volpe Research Center
Edge chipping is a common problem with brittle materials such as ceramics used for dental restorations, consumer wares, substrates and wafers, and advanced ceramic structural applications. Concentrated contact forces applied near an edge can cause a flake to pop off. Knappers have chipped rocks and stones for thousands of years in order to make tools such as arrowheads and axes. Usually, however, edge chipping is a nuisance and can cause unwanted failures. In the 1980s, the National Physical Laboratory in London began studies to quantify the edge chipping resistance of engineering materials. Their work emphasized linear force versus distance trend analysis, but more extensive recent testing has revealed nonlinear trends. Dr. Janet Quinn first applied the edge chipping test to dental materials in the late 1990s during her PhD project at the University of Maryland with Prof. I. Lloyd. Edge chipping is an interesting mechanical engineering and materials science topic. In this presentation, a new model for edge chipping resistance is presented. It is based on energy balances between indenter work, and material deformation and fracture responses.