We report new compositions of γ/γ′ Co base super alloys with low mass density where the strengthening γ′ precipitates Co₃(Al_0.45V_0.33Nb_0.21) are stabilised with a systematic replacement of Mo with V in Co–10Al–5Mo–2Nb (all in at.%) superalloy. The γ/γʹ microstructure is found to be metastable in nature that decomposes into equilibrium phases after 200 h of aging at 800 °C. Diffraction and atomic-scale compositional analysis reveal that phases are a γ-Co solid solution with composition Co-6.9Al–5V-1.4Nb, a B2 ordered Co(Al,V) phase with composition Co-34.6Al-5.6V and a DO₁₉ ordered Co₃Nb phase with composition Co-23.4Nb-1.6Al. Addition of 30 at.% Ni to the Co–10Al–5V–2Nb superalloy increases the γ′-solvus temperature to 1017 °C with improved high temperature strength and stability, concomitantly achieving a yield strength of 701 ± 9 MPa at 770 °C. The γ/γʹ microstructure of the alloy is found to be stable at 800 °C and 900 °C till 1000 h. Vanadium addition, therefore, have marked beneficial effect in cobalt base superalloys indicating good potential for future alloy development.

我们报告了具有低质量密度的γ/γ′Co基超级合金的新成分，其中通过在Co–10Al–5Mo–中将V替换为Mo，稳定了增强的γ'沉淀Co ₃（Al _0.45 V _0.33 Nb _0.21）。 2Nb（全部以原子％计）超合金。γ/ γʹ的微观结构在本质上是亚稳态的，在800°C老化200 h后分解为平衡相。衍射和原子尺度组成分析表明，该相为具有Co-6.9Al-5V-1.4Nb组成的γ-Co固溶体，具有Co-34.6Al-5.6V组成的B2有序Co（Al，V）相。 DO ₁₉订购的Co ₃组成为Co-23.4Nb-1.6Al的Nb相。在Co–10Al–5V–2Nb超级合金中添加30 at。％的Ni，可将γ'固溶线温度提高到1017°C，从而提高了高温强度和稳定性，从而 在770°C时达到701 ± 9 MPa的屈服强度 。发现合金的γ/ γʹ微观结构在800°C和900°C直至1000 h都稳定。因此，钒的添加对钴基高温合金具有明显的有益作用，表明未来合金的开发潜力很大。