Processing of Novel Nanoparticle Dispersion Strengthened Ceramics for Improved Mechanical Performance
Abstract
Results from a previous study carried out by the Lehigh group demonstrated A12O3:SiC nanocomposites exhibited superior mechanical behavior relative to single phase alumina only when the samples had been annealed (2 h at 1300 deg C in argon) subsequent to industrial machining. These results were rationalized by postulating that on annealing of the machined specimens: (a) The extent of healing of grinding induced flaws is more significant in the nanocomposite than in alumina. (b) The machining induced residual stresses are relaxed to a lesser degree in the nanocomposite than in alumina. Further model studies have now been carried out which provide definitive evidence that both of the above assumptions are correct. Observation of indentation induced cracks both prior to, and after annealing, revealed that in the nanocomposite cracking is predominantly transgranular, and crack healing takes place on annealing. For the case of single phase alumina, however, the crack morphology is predominantly intergranular, and annealing causes crack growth.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 14, 1993
- Accession Number
- ADA275965
Entities
People
- Helen M. Chan
- I. Chou
- Jingtian Fang
- Martin P Harmer
- Matthew P. Thompson
Organizations
- Lehigh University