Yeh Chun-Liang, Chen Yu-Ting
Department of Aerospace and Systems Engineering, Feng Chia University, Taichung 40724, Taiwan.
Materials (Basel). 2025 Mar 14;18(6):1293. doi: 10.3390/ma18061293.
The production of TiAlC was investigated by self-propagating high-temperature synthesis (SHS) using the sample compacts composed of elemental powders with or without TiC and TiH additions. The influence of Al, carbon, TiC, and TiH was explored on the combustion sustainability, combustion velocity and temperature, and phase composition and microstructure of the product. The experimental results indicated that the elemental sample with an Al-excess composition increased the combustion velocity and improved the formation of TiAlC, but the sample with a carbon-deficient composition produced the opposite effect. Although both TiC and TiH additions decreased combustion exothermicity, an appropriate amount of TiC enhanced the yield of TiAlC. However, the incomplete decomposition made TiH unsuitable as a source of Ti and resulted in a low yield of TiAlC. In this study, the final product containing the highest content of TiAlC was synthesized from the Al-excess and TiC-added sample of 2.5Ti + 1.2Al + 1.5C + 0.5TiC, and the product was composed of 89.3 wt.% TiAlC, 5.9 wt.% TiAlC, and 4.8 wt.% TiC. A reaction mechanism was proposed for the formation of TiAlC by SHS, which involved three exothermic reaction steps sequentially producing TiC, TiAlC, and TiAlC. The as-synthesized TiAlC grains were in the shape of thin platelets with a thickness of about 1.0 μm, and a layered structure formed by closely stacked platelets was clearly observed.
采用自蔓延高温合成法（SHS），以添加或不添加TiC和TiH的元素粉末组成的样品压坯来研究TiAlC的制备。探究了Al、碳、TiC和TiH对燃烧可持续性、燃烧速度和温度以及产物的相组成和微观结构的影响。实验结果表明，Al过量组成的元素样品提高了燃烧速度并促进了TiAlC的形成，但碳含量不足的样品则产生相反的效果。虽然添加TiC和TiH都会降低燃烧放热，但适量的TiC提高了TiAlC的产率。然而，TiH分解不完全，不适宜作为Ti的来源，导致TiAlC产率较低。在本研究中，由2.5Ti + 1.2Al + 1.5C + 0.5TiC的Al过量且添加TiC的样品合成了TiAlC含量最高的最终产物，该产物由89.3 wt.%的TiAlC、5.9 wt.%的TiAlC和4.8 wt.%的TiC组成。提出了通过SHS形成TiAlC的反应机理，该机理涉及依次生成TiC、TiAlC和TiAlC的三个放热反应步骤。合成的TiAlC晶粒呈薄片状，厚度约为1.0μm，清晰观察到由紧密堆叠的薄片形成的层状结构。
