Dual-phase nanoprecipitation and strengthening-toughening of Nb-Si-based alloys

As a metal-ceramic in-situ composite, toughening Nb-Si alloys by regulating reinforcement is both challenging and crucial. In this work, controlled dispersion precipitation of dual-phase nanoparticles is achieved through quenching and aging treatment, including nanoscale rod-shaped Cr₂Nb and granular γ-Nb₅Si₃. The orientation relationship between precipitates and Nbss matrix follows ((Formula presented.) 20)_Cr2Nb // (01 (Formula presented.))_Nbss, [(Formula presented.) 0]_Cr2Nb // [3 (Formula presented.)]_Nbss and (1 (Formula presented.) 00)_γ-Nb5Si3 // (10 (Formula presented.))_Nbss, [11 (Formula presented.) 3]_γ-Nb5Si3 // [010]_Nbss. The appropriate precipitation of Cr₂Nb and γ-Nb₅Si₃ nanoparticles increases the toughness of the initial alloy by 51%, reaching 16.78 MPa·m^1/2. This result provides an effective approach and theoretical basis for regulating nano-reinforcements to improve the properties of the composites.