A comparison of pressure compaction and diametral compression tests for determining granule strengths
- Sandia National Labs., Albuquerquen, MN (United States)
Pressure compaction (P-C) tests were used to characterize the strength of ceramic granules. When compaction data are plotted as relative density of the compact versus the compaction pressure two linear regions are generally observed. The intersection of these regions, which is known as the {open_quotes}breakpoint,{close_quotes} has been used as a semi-quantitative measure of granule strength. Comparisons were made between the P-C breakpoint and strengths of 150-200 {mu}m diameter ZnO, TiO{sub 2} (rutile), and lead magnesium niobate - lead titanate (PMN-PT) granules, where the strengths were determined by diametral compression (D-C) tests. At high compaction pressures the compliance of the die itself is significant and was accounted for in the analyses. Tests were conducted at different compaction rates, and with different aspect ratio compacts. High aspect ratios and loading rates decrease the slope of the second linear portion of the compaction curve and produce higher apparent P-C breakpoints. Comparison of the P-C breakpoint to the average D-C strength indicates that the D-C strength is approximately fifty percent higher for PMN-PT granules. To eliminate the uncertainty in the results due to irregular granules sizes and shapes, comparisons were also made for uniform size (210 {mu}m) glass spheres. In this case the average D-C strength coincided with a second breakpoint in the P-C data, which occurred after compaction by a mechanism of bridge formation and collapse had ceased.
- Research Organization:
- Sandia National Laboratory
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 229989
- Report Number(s):
- CONF-9505249--
- Country of Publication:
- United States
- Language:
- English
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