Chapter 40. Effect of Microstructure on Abrasive Machining of Advanced ceramics
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1995 The American Ceramic Society
A Collection of Papers Presented at the 96th Annual Meeting and the 1994 Fall Meetings of the Materials & Equipment/Whitewares/Refractory Ceramics/Basic Science: Ceramic Engineering and Science Proceedings, Volume 16, Issue 1
How to Cite
Xu, H. H. K. and Jahanmir, S. (1995) Effect of Microstructure on Abrasive Machining of Advanced ceramics, in A Collection of Papers Presented at the 96th Annual Meeting and the 1994 Fall Meetings of the Materials & Equipment/Whitewares/Refractory Ceramics/Basic Science: Ceramic Engineering and Science Proceedings, Volume 16, Issue 1 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314616.ch40
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1995
Print ISBN: 9780470375341
Online ISBN: 9780470314616
Scratching, grinding, and flexure tests were performed to investigate the effect of microstructure on material removal mechanisms and damage tolerance of different ceramic materials. The materials included glass-ceramics, aluminas, silicon carbides, and silicon nitrides. Among these are materials with weak grain boundaries and interphase boundaries possessing rising toughness curves (T-curves), and materials with more homogeneous microstructure and/or strong grain boundaries possessing single-valued toughness. The weak grain boundaries suppress the development of long cracks, and promote instead the formation of intergranular microcracks. Different mechanisms of material removal are therefore observed: macrocrack chipping in the homogeneous materials, and grain dislodgement in the materials with weak grain boundaries and interphase boundaries. The flexural strength of ground specimens was measured as a function of the depth of cut in surface grinding to assess the influence of microstructure on damage tolerance. Whereas the homogeneous materials showed a drastic strength degradation from grinding-induced subsurface cracks relative to as-polished specimens, the materials with weak grain boundaries exhibited very little strength loss. The results of this study suggest a route to microstructural design and tailoring of ceramics for a twofold benefit: improved machinability through easy intergranular microfracture, and enhanced tolerance to machining-induced damage.