Inconel 718合金在580℃下水蒸气环境中的氧化行为及摩擦学性能

Oxidation Behavior in Water Vapor and Tribological Property in Atmosphere with 60%Relative Humidity at 580 ℃ for Inconel 718 Alloy

通过高温氧化和高温摩擦试验研究了Inconel 718合金在580℃动态纯水蒸气环境中的氧化行为及高温摩擦学性能。结果表明:Inconel 718合金在580℃动态纯水蒸气环境中的氧化动力学曲线遵循两阶段直线规律;与在干燥空气中不同,Inconel 718合金在高温水蒸气中获得的氧化产物粗大,且有网状裂纹存在,但二者成分类似,主要由NiFe_(2)O_(4)和少量的NiO,Cr_(2)O_(3)和Fe_(2)O_(3)组成。随摩擦载荷增加,Inconel 718合金在580℃时的摩擦系数逐渐减小,而磨损率逐渐增加;其在2 N载荷下的磨损机制主要为粘着磨损,而在高于5 N载荷下的磨损机制主要为疲劳磨损和磨粒磨损。

The oxidation behavior of Inconel 718 alloy in flowing water vapor and the wear performance in atmosphere of 60% relative humidity at 580 ℃ were investigated respectively via tubular furnace with an adjustable steam supply unit and a ball-disc type high temperature friction and wear tester. The results showed that the oxidation kinetic curves of Inconel 718 alloy in flowing water vapor at 580 ℃ followed a double linear law approximately. In comparison to those formed in dry air, the oxidation products formed in high-temperature water vapor were coarse with network-like cracks. However, the composition of oxidation products formed in water vapor and dry air were more or less the same, which all composed mainly of NiFe_(2)O_(4)and small amount of NiO, Cr_(2)O_(3), and Fe_(2)O_(3). Beneath the oxide scale, a Cr-depletion region was found. On the other hand, the friction coefficient of Inconel 718 alloy decreased at 580 ℃ with the increase of friction load, while the wear rate increased gradually. The wear mechanism of Inconel 718 alloy by 2N was mainly adhesive wear, while the wear mechanism was mainly fatigue wear and abrasive wear above 5N.