Effect of Aluminum on High Temperature Oxidation Resistance of Alloy HK40
Al对HK40合金高温抗氧化行为的影响

The high temperature oxidation resistance of HK40 alloys with different amount of Al in Ar atmosphere was investigated.The surface morphology and the phases in the oxide scale were analyzed using SEM and XRD,respectively.Experimental results indicated that after Al addition the formed AI2O3 scale on the alloy surface at high temperature was uniform,consequently improved the alloy oxidation resistance.The optimum high-temperature oxidation resistance was achieved with the addition of 6 mass%Al.The oxidation mass gains of the alloy complied with a parabolic law at 1100°C,and oxidation resistance of the allotys was significantly improved with the increase of aluminum content.At high temperature,the formed oxide scales consisted of Cr2O3, CrMn1.5O4,MnCr2O4 and Al2O3,and the amount of Al2O3 in oxide scales increased with the increase of aluminum content,while the presence of aluminum improved the surface homogeneity of oxide scale,and the content of Fe,Ni elements of the oxide scale is much lower than that of the alloys.