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为探讨晶粒尺寸变化对三元复相合金氧化行为的影响,采用机械合金化制备了纳米晶三元Cu-20Ni-20Cr合金,并对比研究了该合金与同成分的铸态合金在700℃～800℃,0.1MPa纯氧气中的氧化行为。结果表明,铸态合金表面没有形成连续的Cr2O3保护膜,而是形成了含有所有组元氧化物及它们复合氧化物的复杂氧化膜结构。纳米晶Cu-20Ni-20Cr合金在700℃时合金表面形成了连续的Cr2O3氧化膜,而800°C时虽没有形成Cr2O3外氧化膜,但氧化膜规则平坦,外层是CuO,中间层是Cu2O,NiO和Cr2O3组成的混合氧化物区,内层则形成了一薄但不连续的Cr2O3层。晶粒细化降低了合金表面形成Cr2O3氧化膜所需活泼组元Cr的临界浓度。
In order to investigate the effect of grain size changes on the oxidation behavior of ternary complex phase alloys, nanocrystalline ternary Cu-20Ni-20Cr alloy was prepared by mechanical alloying. 800 ℃, 0.1MPa pure oxygen in the oxidation behavior. The results show that there is no continuous Cr2O3 protective film formed on the as-cast alloy surface, but a complicated oxide film structure containing all the elemental oxides and their complex oxides is formed. The nanocrystalline Cu-20Ni-20Cr alloy forms a continuous Cr2O3 oxide film on the alloy surface at 700 ℃, while the Cr2O3 oxide film is not formed at 800 ° C, but the oxide film is flat and regular, the outer layer is CuO and the middle layer is Cu2O , NiO and Cr2O3 mixed oxide zone, the inner layer is formed a thin but not continuous Cr2O3 layer. Grain refinement reduces the critical concentration of Cr, an active constituent required for the formation of a Cr2O3 oxide film on the alloy surface.