Heterostructure design and strengthening of TC11 alloy based on interfacial β phase

Rational microstructure design is critical for achieving the excellent comprehensive properties in metallic materials. In this work, we optimized the strength-ductility balance of the quenched TC11 alloy by engineering a heterostructure through tailoring the β phase at the α p /β t interface. The formation of this phase was governed by the redistribution of β-stabilizing element Mo, which was strengthened by pre-deformation solution treatment. The high-density dislocations introduced by deformation significantly promoted Mo enrichment at the α p /β t interfaces. Therefore, the high-temperature β phase could be effectively stabilized and retained up to room temperature, becoming the interfacial β phase. During the aging treatment, this phase partially precipitated 10 nm-scaled α lamellae, which constitute a heterostructure together with submicron-scaled α lamellae formed from martensite decomposition and coarsening. Based on the fine-grain strengthening and heterogeneous deformation induced strengthening, this heterostructured alloy successfully achieved an ultrahigh strength of ∼1429 MPa, comparable to that of martensite alloys. Meanwhile, a superior ductility of ∼9.7 % was maintained and this significantly surpassed that of the latter.