稀土元素Ce与Y对JG4246A合金高温氧化行为的影响

Effects of rare earth elements Ce and Y on high temperature oxidation behavior of JG4246A alloy

在第二代高温合金JG4246A中分别添加不同含量的稀土元素Ce和Y,得到含0.012Ce(质量分数,%,下同)、0.017Ce、0.034Y、0.061Y四种合金铸锭,研究了在1100℃下Ce与Y对合金高温抗氧化性能的影响。采用X射线衍射仪(XRD)及扫描电镜(SEM)分析了氧化膜的物相组成以及氧化表面的形貌。结果表明,JG4246A合金在1100℃空气中恒温氧化过程中,添加稀土元素可以减少合金的氧化质量增加,氧化动力学符合抛物线规律;相对于稀土元素Y,Ce对减缓JG4246A合金的高温氧化速率的作用更显著;稀土元素的添加没有改变氧化膜的表面形貌,但是生成的尖晶石型氧化物使氧化膜更加致密,能够抑制阳离子的向外扩散,降低氧化反应速率,从而提高高温抗氧化性能。

In the secondary generation superalloy JG4246A,rare earth elements Ce and Y were added to obtain four kinds of tested alloy ingots with addition of 0.012Ce(mass fraction,%,the same below),0.017Ce,0.034Y and 0.061Y,respectively.The effects of Ce and Y on high temperature oxidation resistance of these alloys at 1100℃were studied.The phase composition and the morphology of oxidized surface were analyzed by means of X-ray diffractometer(XRD)and scanning electron microscope(SEM).The results indicate that the oxidation mass gain of the JG4246A alloy can be reduced by adding rare earth elements during the isothermal oxidation process at 1100℃in air,and the oxidation kinetics of the JG4246A alloys conforms to parabolic law.Compared to the rare earth element Y,Ce has a more significant effect on slowing down the high temperature oxidation rate of the JG4246A alloy.The addition of rare earth elements does not change the surface morphology of the oxide film,but the spinel oxide makes the oxide film more compact,which can inhibit the outward diffusion of cations and reduce the oxidation reaction rate,thus improving the oxidation resistance at high temperature.