The synergistic effect of Mo and Zr additions on microstructure evolution, room-temperature fracture toughness and microhardness of Nb-22Ti-15Si-xMo-yZr (x = 4,8, y = 3,6) alloys manufactured by laser directed energy deposited (L-DED) have been investigated. The major phases in as-deposited 4Mo-3Zr alloy are Nb solid solution (Nbss), Nb₃Si and γ-Nb₅Si₃. The Nb₃Si phases disappear with increasing Mo content to 8 at.% or increasing Zr content to 6%. γ-Nb₅Si₃ precipitates formed in the Nbss of as-deposited xMo-yZr alloys due to the cyclic re-heating, and the γ-Nb₅Si₃ precipitates and Nbss matrix exhibits orientation relationship (OR) of [001]_Nbss//[$\overline{1}$112]_γ and (110)_Nbss//(01$\overline{1}$0)_γ in as-deposited 4Mo-6Zr alloy. The microstructure of xMo-yZr alloys became relative homogeneity and the Nbss matrix showed the better continuity after the heat treatment (1400 °C/30 h). The Nb₃Si phase has transformed into Nbss and α-Nb₅Si₃ with the OR have been determined as {100}_Nbss//{100}_α and{111}_Nbss//{111}_α in the heat-treated 4Mo-3Zr alloy. When Mo content increase to 8at.%, a part of γ-Nb₅Si₃ phase also transformed into the α-Nb₅Si₃ phase with the OR have been determined as {11$\overline{2}$0}_γ//{110}_α and {10$\overline{1}$0}_γ//{111}_α after heat treatment. Among the as-deposited alloys, the 4Mo-6Zr alloy has the highest fracture toughness K_Q with the lowest hardness. The average K_Q of 4Mo-6Zr and 8Mo-6Zr alloys increased by 28% and 30% after the heat treatment, and reached 13.61 and 11.43 MPa•m^1/2, respectively. The hardness of Nb-22Ti-15Si-xMo-yZr alloys is significantly decreased after the heat treatment.

Mo和Zr添加对激光定向能制备的Nb-22Ti-15Si- x Mo- y Zr ( x = 4,8, y = 3,6 )合金显微组织演变、室温断裂韧性和显微硬度的协同作用已研究沉积（L-DED）。沉积态4Mo-3Zr合金的主要相是Nb固溶体（Nbss）、Nb ₃ Si和γ-Nb ₅ Si ₃。随着Mo含量增加到8at.%或Zr含量增加到6% ，Nb ₃ Si相消失。γ-Nb ₅ Si ₃析出物在沉积态x Mo- y的 Nbss 中形成Zr合金由于循环再加热，γ-Nb ₅ Si ₃析出物和Nbss基体呈现[001] _Nbss //[$\overline{1}$[112] _γ和 (110) _Nbss //(01$\overline{1}$0)沉积态 4Mo-6Zr 合金中的_γ。x Mo- y Zr 合金的显微组织变得相对均匀，Nbss 基体在热处理后（1400 °C/30 h）表现出更好的连续性。Nb ₃ Si 相已转变为 Nbss 和 α-Nb ₅ Si ₃与 OR 已确定为 {100} _Nbss //{100} _α和{111} _Nbss //{111} _α在热处理的 4Mo -3Zr合金。当Mo含量增加到8at.%时，一部分γ-Nb ₅ Si ₃相也转变为α-Nb ₅ Si ₃ 与 OR 的相位已确定为 {11$\overline{2}$0} _γ //{110} _α和 {10$\overline{1}$0} _γ //{111}热处理后的_α。间所沉积的合金中，4Mo-6Zr合金具有最高的断裂韧性ķ _Q具有最低硬度。热处理后4Mo-6Zr和8Mo-6Zr合金的平均K _Q分别提高了28%和30% ，分别达到13.61和11.43 MPa•m ^1/2。Nb-22Ti-15Si- x Mo - y Zr 合金的硬度在热处理后显着降低。