Control of Fracture Damage in Precision Machining of Ceramics

点击翻译按钮获取中文摘要

The project will study damage-free ultraprecision machining processes on advanced ceramic materials. The goal is to generate an improved understanding of the material-removal processes that occur in nanometer-scale grinding of ceramics, and ultimately to be able to control grinding damage generation in-process. The research plan includes extending the ductile-regime grinding model to include toughened ceramics, and defining grinding machining parameters required for these materials. Further modification of the grinding process by the introduction of engineered chemomechanical effects on the ceramic surface will be developed, through controlled surface toughening. A goal of this research is to develop a real-time acoustic emissions feedback system to measure and control grinding damage in-process. Through preliminary research, the sensitivity of acoustic emissions to material removal processes has been established. Understanding the basis of that sensitivity and its relationship to subsurface fracture generation will guide development of an effective control strategy. It is expected that as a direct result of this research: (1) models for ductile-regime grinding, developed by the principal investigator, will be extended to include tough, advanced ceramic materials; (2) chemomechanical effects in machining of ceramics will be studied with regard to their potential for altering the surface properties of ceramics, thereby enhancing the machinability of candidate ceramic materials; and (3) fracture-generated acoustic emissions signals will be analyzed in a basic study of the these elastic waves and their relationship to grinding-induced subsurface damage.