Chapter 9. Improvement in Working Limit for Ceramic Components by Using Crack-Heal
- Rajan Tandon,
- Andrew Wereszczak and
- Edgar Lara-Curzio
Published Online: 27 MAR 2008
Copyright © 2007 The American Ceramics Society
Mechanical Properties and Performance of Engineering Ceramics II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 2
How to Cite
Nakao, W., Osada, T., Ono, M., Takahashi, K. and Ando, A. K. (2008) Improvement in Working Limit for Ceramic Components by Using Crack-Heal, in Mechanical Properties and Performance of Engineering Ceramics II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 2 (eds R. Tandon, A. Wereszczak and E. Lara-Curzio), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291313.ch9
- Published Online: 27 MAR 2008
- Published Print: 1 JAN 2006
Print ISBN: 9780470080528
Online ISBN: 9780470291313
Cracks, which introduced during machining, could reduce the reliability of structural ceramics significantly, because their sizes decide the strength of the ceramics. Thus, one must conduct the carefully planed machining and polishing in order to prevent the introduction of large cracks. The effects of crack–healing process on the fracture strength and improvement of working limit were investigated in the present study.
At the center of specimens, a semicircular groove having radius of 2 mm and depth of 0.5 mm was made by diamond drill with the cutting depth by one pass raging from 5 μm to 15 μm.
The specimens having a semicircular groove were subjected to the crack–healing treatment at temperatures ranging from 1573 K to 1673 K for 1 – 10 h in air. The bending tests of the as–machined specimens and healed specimens were also performed at room temperature.
As the cutting depth increased, the fracture strength measured for the machined specimens decreased. Comparison of these values with the bending strength of specimens without cracks revealed that machining with cutting depth of 2 (xm is the working limit not to reduce the strength. On the contrary, crack–healing at 1673 K for 10 h can completely eliminate cracks introduced during machining even with cutting depth of 15 μm, and then recovering the local fracture strength. Therefore, this study demonstrates that using crack–heal can improve working limit for ceramic components