新型Co-Al-W合金高温氧化激活能研究

钴-铝-钨合金是一种由γ′-Co3(Al,W)相沉淀强化的新型钴基高温合金。测定了该合金在800和900℃下空气氧化增重动力学数据,通过线性拟合得到合金在不同温度下的氧化速率常数。根据氧化速率常数的Arrhenius关系,计算合金在800和900℃高温环境中的氧化激活能。研究发现,7.5W、9W和10.7W合金中9W合金氧化激活能最高;合金元素Mo、Nb、Ta和Ti加入之后,Co-Al-W合金的氧化增重和氧化激活能发生变化,由此可以预测该合金在高温环境中的抗氧化能力。

Activation Energy of Oxidation of Novel Co-Al-W Superalloys at High Temperatures

Co-Al-W alloy is a novel Co-base superalloy, with the precipitation strengthening phase of ternary compound γ′-Co3(Al,W). The kinetic data of oxidation mass gain were measured for the Co-Al-W alloy at 800 and 900 oC in air, and the oxidation rate constants at different temperatures were determined by the relevant linear fitting. According to Arrhenius relation of the oxidation rate constants, the activation energy of oxidation was derived for this alloy at 800 and 900 oC. It is found that 9W alloy has the highest value of activation energy of oxidation among 7.5W, 9W and 10.7W at different temperatures. The addition of refractory elements Mo, Nb, Ta and Ti can change the mass gain and activation energy of oxidation of the Co-Al-W alloy; therefore, the oxidation resistance of the superalloy at high temperatures can be forecast.