The abrasive wear of sintered titanium matrix-ceramic particle reinforced composites

Particulate (TiC, TiB2 or Si3N4) reinforced Ti composites were produced by vacuum sintering (at 1400 degrees C for 2 h). Ti + TiC composites could be sintered to high fractional densities (> 93%), even at high TIC loadings (e.g., 40 volume percent (vol%)). No reactions were observed to occur between the Ti and TiC. By contrast, the Ti and TiB2 and Ti and Si3N4 reacted to form composites consisting of Ti, TiB and TiB2 and alpha-Ti(N), Ti5Si3, Ti3Si, and Ti2N, respectively. As a consequence, Ti was consumed and/or the reaction products intrinsically generated porosity during sintering. These composites were more difficult to consolidate via solid state sintering, particularly at higher volume fractions. Despite the porosity, the composites were more wear resistant (pin-on-drum abrasive wear against 100 mu m garnet particles) than unreinforced Ti, with the exception of the Ti + 2.5 vol% TiB, and Ti + less than or equal to 10 vol% TiC composites. The ranking of microhardness and abrasion wear resistance of the composites was as follows: (hardest, most wear resistant) Ti + Si3N4 (i.e., alpha-Ti(N), +Ti5Si3, Ti3Si, and Ti2N)>> Ti + TiB2 >> Ti + TiC (softest, least wear resistant). The microhardness coupled with the apparent strength of the chemical interface that developed between the constituent composite phases was responsible for the observed wear behavior. (C) 1999 Published by Elsevier Science S.A. All rights reserved.