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 f
orm composites consisting of Ti, TiB and TiB2 and alpha-Ti(N), Ti5Si3, Ti3S
i, and Ti2N, respectively. As a consequence, Ti was consumed and/or the rea
ction products intrinsically generated porosity during sintering. These com
posites were more difficult to consolidate via solid state sintering, parti
cularly at higher volume fractions. Despite the porosity, the composites we
re more wear resistant (pin-on-drum abrasive wear against 100 mu m garnet p
articles) 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 mic
rohardness 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 mi
crohardness coupled with the apparent strength of the chemical interface th
at developed between the constituent composite phases was responsible for t
he observed wear behavior. (C) 1999 Published by Elsevier Science S.A. All
rights reserved.