Ti₂AlNb-based intermetallic compounds are considered as a new category of promising lightweight aerospace materials due to their balanced mechanical properties. The aim of this study was to evaluate monotonic and cyclic deformation behavior of an as-cast Ti-22A1-20Nb-2V-1Mo-0.25Si (at.%) intermetallic compound in relation to its microstructure. The alloy containing an abundant fine lamellar O-Ti₂AlNb phase exhibited a good combination of strength and plasticity, and superb fatigue resistance in comparison with other intermetallic compounds. Cyclic stabilization largely remained except slight cyclic hardening occurring at higher strain amplitudes. While fatigue life could be described using the common Coffin-Mason-Basquin equation, it could be better predicted via a weighted energy-based approach. Fatigue crack growth was characterized mainly by crystallographic cracking, along with fatigue striation-like features being unique to appear in the intermetallics. The results obtained in this study lay the foundation for the safe and durable applications of Ti₂AlNb-based lightweight intermetallic compounds.

基于Ti ₂ AlNb的金属间化合物由于其平衡的机械性能而被视为有前途的轻质航空航天材料的新类别。这项研究的目的是评估铸态Ti-22A1-20Nb-2V-1Mo-0.25Si（at。％）金属间化合物的单调和周期性变形行为及其微观结构。含有大量细小片状O-Ti ₂的合金与其他金属间化合物相比，AlNb相表现出强度和可塑性的良好组合，并且具有出色的抗疲劳性。除了在较高的应变幅度下发生轻微的循环硬化外，很大程度上保持了循环稳定性。尽管可以使用通用的Coffin-Mason-Basquin方程描述疲劳寿命，但可以通过基于能量的加权方法更好地预测疲劳寿命。疲劳裂纹扩展的主要特征是晶体学裂纹，金属间化合物中独特地出现了疲劳条纹状特征。这项研究中获得的结果为基于Ti ₂ AlNb的轻质金属间化合物的安全耐用应用奠定了基础。