Abstract
Ti3SiC2 has many salient properties including low density, high strength
and modulus, damage tolerance at room temperature, good machinablity,
and being resistant to thermal shock and oxidation below 1100?C.
However, the low hardness and poor oxidation resistance above 1100?C
limit the application of this material. The poor oxidation resistance
at temperatures above 1100?C was because of the absence of protective
layer in the scale and the presence of TiC impurity phase. TiC impurity
could be eliminated by adding a small amount of Al to form Ti3Si(Al)C2
solid solutions. Although the high-temperature oxidation resistance
was significantly improved for the Ti3Si(Al)C2 solid solutions, the
strength at high temperatures was lost. One important way to enhance
the high-temperature strength is to incorporate hard ceramic particles
like SiC. In this article, we describe the in situ synthesis and
simultaneous densification of Ti3Si(Al)C2/SiC composites using Ti,
Si, Al, and graphite powders as the initial materials. The effect
of SiC content on high-temperature mechanical properties and oxidation
resistance were investigated. The mechanisms for the improved high-temperature
properties are discussed.
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