WITHDRAWN: Temperature-influenced Substitution of Si in Ti3(Si,Al)C2  Solid Solution

Abstract

High-pure Ti3(Si,Al)C2 solid solutions were synthesized in the range of 1473 to 1773K. The microstructures and chemical compositions of all samples were characterized by X-rays diffraction (XRD) and scanning electron microscope (SEM). It was worthy noted that experimentally determined lattice parameter c of Ti3(Si,Al)C2 crystal decreased with the increasing of sintering temperature. The contents of Si and Al elements in solid solution were conducted by Vegard’s Law. Gibbs energy differences (△G) of substitution behaviors of Si at different temperatures were also listed. With the increase of temperature, △G of Eq. Ti3(Si0.75Al0.25)C2+0.25Si→Ti3SiC2+0.25Al were negative and decreased gradually, which means that the transformation from Ti3(Si,Al)C2 to Ti3SiC2 was spontaneous and had a greater tendency in higher temperatures. By analyzing the experiment data, a possible mechanism of the substitution process of Si in various temperatures was determined.