High Temperature Reaction Between Ti₃AlC₂and Al

Ti3AlC2is a member of Ternary layered ceramic, providing with many advantages of metal and ceramic materials, including good electrical conductivity, thermal conductivity, lower hardness, high bending strength, high temperature resistance, oxidation resistance and other features.Ti3AIC2is the ideal enhanced phase of the metal matrix composites. In this article, the high purity of Ti3AlC2powder is prepared by non-pressure vacuum sintering, and the reaction products and processes of high temperature between Ti3AlC2and Al are analyzed by XRD, SEM. The Ti3AlC2/Al composites are prepared by vacuum hot-press sintering.First of all, the high purity powder of Ti3AlC2is prepared by non-pressure sintering. The raw material of TiC, Ti and Al should be mechanical milled in agate ball and polyurethane jar mill at a speed of250-300r/min for8-10h in ethanol medium, in a ratio of8:1between grinding media and material. The product of the reaction is analyzed using XRD, and factors of the process are discussed. Results demonstrate that the high purity Ti3AlC2/Al is made by mixing TiC:Ti:Al in a ratio of2:1:1.2at1643K for20minutes.Prior to the reaction, the probability reaction of products is analyzed through the phase diagram, and the sintering temperature is873K-973K. The effects on product are analyzed in a method of XRD by changing the sintering temperature, holding time and the molar ratio of raw materials. The results show that new phases Al3Ti and Al4C3are emerged when sintering at the temperature of923K over120minutes. Increasing the holding time and temperature is propitious to the following reaction, Ti3AlC2+Alâ†'Al3Ti+Al4C3, and it is found that lmol Ti3AlC2will reactive with1Omol Al.The block specimens of Ti3AlC2and Al powder are made by the hot-press sintering. The microstructure of boundary is analyzed by SEM, EDS and XRD. The results show that Al diffuses into Ti3AlC2and then reactive, producing Al3Ti, Al4C3.Ti3AlC2/Al composites are prepared in hot-press sintering at a temperature under the923K for a short time, avoiding the reaction between of Al and Ti3AlC2. Al/10%Ti3AlC2composites are made in the conditions of900K,10minutes and30Mpa in the paper. The density of the composite material measured through Archimedes drainage method is up to98%, so the Al/Ti3AlC2composites can be made by powder metallurgy.