HOT-SHOCK CONSOLIDATION AND MECHANICAL THERMAL PROPERTIES OF TI-AL-C COMPOSITES USING EXPLOSIVE SHOCK ENERGY AND COMBUSTION SYNTHESIS/

Fabrication of dense Ti-Al-C system composites by hot-shock consolidat ion was attempted, Ti (mean particle size : 45 mu m), Al (17 mu m) and graphite (1-2 mu m) paw powders were mixed by various molar ratios, a nd the mixtures tapped into a powder charging container, followed by t he self-propagating high temperature synthesis [SHS] reaction, Immedia tely after, the obtained porous products were densified by underwater- shock consolidation using the detonation of explosive charge, This pro cess was completed in about 20 s, The specimens were characterized by XRD experiments, density measurements, micro Vickers hardness tests, m icrostructural observations and oxidation resistance tests, As a resul t, three kinds of intermetallic compounds (TiAl, Ti2Al and Ti3Al), and two kinds of ceramics (TiC and Ti4Al2C2) were detected, mainly by the XRD experiments. The main phase detected for the compositions TiC-40 mol%TiAl and TiC-60 mol%TiAl was the Ti4Al2C2 phase. Ii is considered that this phase was produced at the high temperature generated by the SHS reaction, Results of its density measurements and micro Vickers ha rdness tests indicated almost the same tendency as those of the Ti-Al system intermetallic compound, In addition, the microstructural observ ations revealed that the composites with compositions between TiC-40 m ol%TiAl and TiC-60 mol%TiAl had a needle-like microstructure. The TIG- IO mol%TiAl composite showed the highest oxidation resistance among th e present specimens, The Ti-Al-C system composites are expected to be novel materials with light weight and excellent heat resistance.