The effects of TaB addition on the Nb-16Si-22Ti-3Al alloy were investigated in this study. The results showed that the Nb-16Si-22Ti-3Al alloy consisted of the Nbss phase, α-NbSi phase, NbSi phase, and Tiss phase. With the addition of TaB increased from 0 to 0.25 at. %, the NbSi disappeared and the eutectic transformation reaction occurred (NbSi → Nbss + α-NbSi), which made the volume fraction of the Nbss phase increased from 38.6% to 50.3%. With the TaB addition further increasing to 2.0 at. %, the α-NbSi became the primary phase, and the microstructure transformed from the Nbss + α-NbSi eutectic structure to the primary α-NbSi and (Nbss + γ-NbSi) hypereutectic structure. The alloy with 0.25 at. % TaB addition had the highest fracture toughness of 10.2 MPa•m due to the refinement of microstructure and the increment of ductile Nbss. The maximum compressive strength of TaB added alloy at room temperature reached 2587.25 MPa in 2.0TaB specimen, owing to the solid solution strengthening of Ta and B, and the increment of the silicides content. Additionally, by comparing the fracture toughness of alloys with TaB addition obtained by three-point bending (SENBs) and indentation methods, respectively, the feasibility of estimating the fracture toughness of NbSi based alloys by the indentation method is demonstrated with an error of below 20%, which provided a basis for subsequent rapid performance characterization.

中文翻译：

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TaB2添加对Nb[sbnd]Si基合金显微组织和力学性能的影响


本研究研究了TaB添加对Nb-16Si-22Ti-3Al合金的影响。结果表明，Nb-16Si-22Ti-3Al合金由Nbss相、α-NbSi相、NbSi相和Tiss相组成。随着TaB的添加从0增加到0.25at。 ％时，NbSi消失并发生共晶转变反应（NbSi→Nbss + α-NbSi），使Nbss相的体积分数从38.6％增加到50.3％。随着TaB添加量进一步增加至2.0。 ％时，α-NbSi成为初生相，组织由Nbss+α-NbSi共晶组织转变为初生α-NbSi和(Nbss+γ-NbSi)过共晶组织。该合金具有0.25 at。由于显微组织的细化和韧性Nbss的增加，% TaB添加的断裂韧性最高，为10.2 MPa·m。由于Ta和B的固溶强化以及硅化物含量的增加，2.0TaB试样中添加TaB的合金室温最大抗压强度达到2587.25 MPa。此外，通过比较三点弯曲法（SENBs）和压痕法分别获得的添加TaB合金的断裂韧性，证明了压痕法估算NbSi基合金断裂韧性的可行性，误差低于20 %，为后续快速性能表征提供了基础。