Development and Assessment of Uniaxial Densification Limit Models for Particulate Bodies with Mono and Bimodal Sized Rigid Spherical Inclusions
Abstract
Ceramics reinforced with diamond inclusions are attractive armor materials due to significant enhancements in hardness. Because hardness depends on the inclusion content, the question that naturally arises is what is the inclusion content limit for a composite particulate body undergoing densification? The answer to which lies within percolation theory. During densification, if the inclusion content exceeds a critical value, a rigid percolated inclusion network forms spanning the shrinking dimension(s) of the densifying body resulting in an abrupt end to densification. This critical value is called the percolation threshold. Formulating the problem in terms of averaged characteristic quantities and making key assumptions, the mathematical challenges of percolation theory are avoided, enabling the development of deterministic models for the uniaxial densification of composite particulate bodies with either mono-sized or bimodal-sized rigid inclusions. Using the models as guidance, hot-pressing experiments were conducted on silicon hexaboride/diamond inclusion powder mixtures to validate model predictions. Overall, model predictions were in excellent agreement with the experimental results. The highest contents achieved were approximately 30 and 40 vol for mono-sized and bimodal-sized diamond inclusions, respectively. Discrepancies between model and experimental results for bimodal-sized diamond indicate the effects of finite particle size differences cannot be disregarded as was assumed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 18, 2020
- Accession Number
- AD1119651
Entities
People
- Anthony A Digiovanni
- Jerry C LaSalvia
- Matthew C. Guziewski
Organizations
- United States Army Research Laboratory