Characterization and Evaluation of TiB2-AlN Composites for Armor Applications
Final rept. Jun 2005-Nov 2008
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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Seven composites with titanium diboride TiB2 and aluminum nitride AlN of varying compositions were consolidated by hot pressing. The compositions examined were 30-vol TiB2 70-vol AlN, 50-vol TiB2 50-vol AlN, and 70-vol TiB2 30-vol AlN. One TiB2 powder was used with three AlN powders two with finer particle sizes and one with larger particle sizes. All the composites were consolidated to near full density. Microstructural, mechanical-property, and ballistic depth-of-penetration DOP evaluations were conducted. Theoretical phase calculations were used to determine and explain the formation of the detected impurities. The flexural strength and mass efficiency results from the four-point bend and DOP tests, respectively, showed that most of the composite compositions performed better than either monolithic TiB2 or AlN material. The increase in fracture toughness from microcrack formation and crack bridging is believed to be the cause of the synergistic effects.