Abstract Spark Plasma Sintering and Hot Isostatic Pressing were used to synthesize coarse-grained and fine-grained Ti3AlC2 specimens. Moreover, Spark Plasma Sintering processing parameters were modified in order to vary the TiC, Al2O3 and TixAly impurity and the porosity contents in the fine-grained samples. The influence of the Ti3AlC2 microstructure on the oxidation resistance was assesed. It is demonstrated that the grain size can drastically modify the oxidation resistance. The higher density of grain boundaries, in fine-grained specimens, increases the number of Al diffusion paths and leads to the formation of a protective alumina scale. In coarse-grained sample, Al diffusion is the rate limiting step of the α−Al2O3 formation and TiO2 is formed simultaneously to alumina. TiC impurities and porosity are demonstrated to be detrimental to the oxidation resistance in the 800 °C–1000 °C temperature range by favouring TiO2 formation. Finally, it is also shown that, for fine-grained specimens, the oxide scale grows very slowly for oxidation times in the range 20–40 days.

中文翻译：

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Ti3AlC2 MAX 相的显微组织-抗氧化性关系

摘要 采用火花等离子烧结和热等静压法合成粗晶和细晶Ti3AlC2试样。此外，为了改变细晶粒样品中的 TiC、Al2O3 和 TixAly 杂质和孔隙率，修改了火花等离子体烧结工艺参数。评估了 Ti3AlC2 微观结构对抗氧化性的影响。结果表明，晶粒尺寸可以显着改变抗氧化性。在细晶粒试样中，晶粒边界的密度较高，增加了铝扩散路径的数量，并导致形成保护性氧化铝氧化皮。在粗晶粒样品中，Al 扩散是 α-Al2O3 形成的限速步骤，而 TiO2 与氧化铝同时形成。TiC 杂质和孔隙率被证明通过有利于 TiO2 的形成而对 800 °C-1000 °C 温度范围内的抗氧化性有害。最后，还表明，对于细晶粒试样，氧化皮在 20-40 天范围内的氧化时间增长非常缓慢。