粉末高温合金FGH4095和FGH4096的抗高温氧化性能

High temperature oxidation resistance of PM superalloys FGH4095 and FGH4096

为研究舰载航空发动机关键部件的氧化腐蚀防护,开展镍基粉末高温合金FGH4095和FGH4096在750~1100℃空气环境中的高温氧化实验,采用静态增重法测定两种合金在不同温度下的氧化动力学曲线,利用金相显微镜、扫描电子显微镜、电子探针分析仪和X射线衍射仪对合金试样表面与截面氧化层的形貌、结构以及组成进行观察和分析。结果表明:FGH4095和FGH4096两种合金在750~900℃时属于完全抗氧化级,在1000~1100℃时属于抗氧化级,而两种合金的实际服役温度在900℃以下,所以在其工作温度范围内抗氧化性能优异。在750~900℃时,两种合金的抗氧化性能相近,无明显差别,氧化膜均未发生剥落。高温氧化后,FGH4095和FGH4096的氧化膜分为两层,内层都是以Al_(2)O_(3)为主,FGH4095的外层由Cr_(2)O_(3),Nb_(2)O_(5)和TiO_(2)组成,而FGH4096的外层仅为Cr_(2)O_(3)和TiO_(2)。在1100℃时,两种合金都发生明显氧化,大量氧化皮破裂,由于合金成分不同,此温度下两种合金的抗氧化性能差别较大,相比之下FGH4095合金具有更好的抗氧化性能。

In order to study the oxidation corrosion protection of key components of carrier aero engine,the high temperature oxidation behavior of the Ni-based powder metallurgy(PM)superalloys FGH4095 and FGH4096 in air at the temperature range of 750-1100℃was investigated.The oxidation kinetics curves were determined by static weighing method.The structure,composition,and morphology of the surface oxide scale as well as its cross section were analyzed by metallographic microscope,scanning electron microscope(SEM),electron probe microanalyzer(EPMA)and X-ray diffractometer(XRD).The results show that two kinds of alloys belong to the grade of full oxidation resistance at 750-900℃and oxidation resistance at 1000-1100℃.The actual service temperature of both alloys is below 900℃,so they exhibit excellent oxidation resistance in their operating temperature range.At 750-900℃,the oxidation resistance of the two alloys is similar without obvious difference.The oxide film is intact without peeling.The oxide films of FGH4095 and FGH4096 are composed of two layers after high temperature oxidation.The internal layer is mainly Al_(2)O_(3).The outer layer of FGH4095 is composed of Cr_(2)O_(3),Nb_(2)O_(5) and TiO_(2).The outer layer of FGH4096 is composed of only Cr_(2)O_(3) and TiO_(2).At 1100℃,both alloys are obviously oxidized and a large number of oxide scales crack.Due to the different compositions of the alloys,the oxidation resistance of the two alloys varies greatly at this temperature.In contrast,FGH4095 alloy exhibits better oxidation resistance.