MAB phases are a family of ternary transition metal borides with a layered crystal structure, that provides them with properties likely to be suitable for applications within extreme environments. Here, we report a computational and experimental examination of the W-Al-B system compared to the isostructural Mo-Al-B system. Utilising DFT calculations, WAlB and MoAlB were found to be thermodynamically favourable compared to their most stable competing phases, with respective total energy differences of -0.15 eV and -0.28 eV at 0 K. Partial substitution of W on the Mo-site of MoAlB was observed for certain solid solution compositions. The experimental results indicate that synthesis of (Mo,W)AlB compounds is driven by in-situ formation of metal boride solid solutions, (Mo,W)B, which further react with Al, Mo-Al, W-Al or (Mo,W)-Al compounds to obtain the MAB phase structure. Finally, reactive hot-pressing was shown to be a promising avenue for the production of dense engineering (Mo,W)AlB-containing components.

MAB相是一类具有层状晶体结构的三元过渡金属硼化物，可为它们提供可能适用于极端环境的性能。在这里，我们报告了W-Al-B系统与同构Mo-Al-B系统相比的计算和实验检查。利用DFT计算，发现WAlB和MoAlB与它们最稳定的竞争相相比在热力学上是有利的，在0 K时各自的总能量差分别为-0.15 eV和-0.28 eV。在MoAlB的Mo位上W的部分取代是观察到某些固溶体成分。实验结果表明（Mo，W）AlB化合物的合成是由金属硼化物固溶体（Mo，W）B的原位形成驱动的，该固溶体进一步与Al，Mo-Al，W-Al或（Mo ，W）-Al化合物以获得MAB相结构。最后，反应热压被证明是生产致密工程（Mo，W）AlB组分的有前途的途径。