The formation mechanism of porous TiAl3 intermetallics from Ti-75 at.% Al powder compact was explored through a continuous sintering process. The exothermic behavior, temperature changes and open porosity were investigated by ranging the sintering temperature from 600°C to 700°C. Results show that a thermal explosion (TE) occurs once the sample temperature reaches to 675°C, upon which it rapidly climbs to 1148°C within 10 s. Visual observation was achieved and revealed the exothermic state at every step, showing the overall heating and instantaneous reaction of TE. The open porosity increased significantly from 24.8% to 58.7% by increasing the sintering temperature from 670°C to 675°C. The reaction mechanism of porous TiAl3 materials in the Ti-75 at.% Al system indicates that sintering at 600°C, 650°C, and 670°C was controlled by atomic diffusion, diffusion-induced TE, and liquid-induced TE reaction, respectively. The diffusion reaction activation energy was 161.5 kJ mol−1 for diffusion-controlled growth of the TiAl3 reaction layer.

中文翻译：

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连续烧结过程中多孔TiAl3金属间化合物的可视化观察及形成机制

通过连续烧结过程探索了 Ti-75 at.% Al 粉末压块形成多孔 TiAl3 金属间化合物的机理。通过将烧结温度范围从 600°C 到 700°C 来研究放热行为、温度变化和开孔率。结果表明，一旦样品温度达到 675°C，就会发生热爆炸 (TE)，然后在 10 秒内迅速攀升至 1148°C。实现了目视观察并揭示了每一步的放热状态，显示了 TE 的整体加热和瞬时反应。通过将烧结温度从 670°C 增加到 675°C，开孔率从 24.8% 显着增加到 58.7%。多孔 TiAl3 材料在 Ti-75 at.% Al 体系中的反应机理表明，在 600°C、650°C 和 670°C 下的烧结受原子扩散控制，分别是扩散诱导的 TE 和液体诱导的 TE 反应。TiAl3 反应层的扩散控制生长的扩散反应活化能为 161.5 kJ mol-1。