DD6单晶高温合金的等温氧化行为

摘要

研究第二代单晶高温合金DD6在1050℃和1100℃下的等温氧化行为,分别采用SEM、XRD和EDS对氧化产物进行分析.结果表明,在1050 ℃和1100℃温度下,DD6合金的100 h氧化动力学曲线遵循亚抛物线规律.在1050℃时,氧化产物分为两层,外层为NiO和少量的Al2O3,内层为Al2O3.而在1100 ℃时,氧化产物分为三层,外层为Al2O3和少量的NiO,中间层为Cr2O3和TaO2,内层由Al2O3组成.在这2种温度下的氧化物下面都形成了无γ’相的区域.%The isothermal oxidation behavior of the second generation single crystal superalloy DD6 was studied at 1050 ℃ and 1100 ℃ in ambient atmosphere.Morphology of oxides was examined by SEM and their composition was analyzed by XRD and EDS.The experimental results show that DD6 alloy obeys subparabolic rate law during oxidation of 100 h at 1050 ℃ and 1100 ℃.The oxide scale exposed at 1050 ℃ is made up of an outer NiO layer with a small amount of Al2O3 and an inner Al2O3 layer.The oxide scale exposed at 1100 ℃ is made up of an outer Al2O3 layer with a small amount of NiO,an intermediate layer,mainly composed of Cr2O3 and TaO2,and an inner A12O3 layer.The γ'-free layer was formed under the oxide scale at two temperatures.