To obtain the balanced mechanical properties of Nb–Si based alloys, the effects of multiple additions of Zr and Y on microstructure, fracture toughness and tensile strength were investigated. The compositions of the alloys were designed as Nb–16Si–23Ti–4Cr–2Al-2Hf-(3Zr-0.6Y), (5Zr-0.3Y) and (5Zr-0.6Y). The addition of Zr promotes silicide transition from α-Nb₅Si₃ to γ-Nb₅Si₃; in 5Zr alloys, the γ-Nb₅Si₃ is the sole silicide. Added Y accelerates the spheroidization rate of silicide during the heat treatment process. The toughness of 3Zr-0.6Y, 5Zr-0.3Y and 5Zr-0.6Y alloys are 23.1, 17.9 and 20.0 MPa m^1/2, respectively. Alloys containing more Y and less Zr have better toughness, accompanied by the greater degree of crack deflections, more microcracks and rougher fracture surfaces. The tensile strength of the three alloys are 919, 1209 and 1159 MPa, respectively. The higher strength of 5Zr alloys is attributed to greater orientation difference and immobile dislocations. The two mechanical properties are balanced successfully in the 5Zr-0.6Y alloy.

为了获得Nb-Si基合金的平衡力学性能，研究了Zr和Y的多次添加对显微组织，断裂韧性和拉伸强度的影响。合金的成分设计为Nb-16Si-23Ti-4Cr-2Al-2Hf-（3Zr-0.6Y），（5Zr-0.3Y）和（5Zr-0.6Y）。Zr的加入促进了从α-Nb的硅化物过渡₅的Si ₃对γ-的Nb ₅的Si ₃ ; 在5Zr合金中，γ-的Nb ₅的Si ₃是唯一的硅化物。添加的Y会加快热处理过程中硅化物的球化速率。3Zr-0.6Y，5Zr-0.3Y和5Zr-0.6Y合金的韧性分别为23.1、17.9和20.0 MPa m ^1/2， 分别。含有更多的Y和更少的Zr的合金具有更好的韧性，同时伴随着更大的裂纹变形，更多的微裂纹和更粗糙的断裂表面。三种合金的抗拉强度分别为919、1209和1159 MPa。5Zr合金的更高强度归因于更大的取向差和不动的位错。在5Zr-0.6Y合金中，两个机械性能成功地达到了平衡。