第三代镍基单晶高温合金1000℃氧化行为研究

Oxidation behaviors of nickel base single crystal superalloy DD33 at 1000℃

研究了镍基单晶高温合金DD33在1000℃下的等温氧化行为。通过扫描电子显微镜、能谱、X射线衍射仪和电子探针X射线显微分析仪等,对氧化膜的相组成、形貌及结构特点与元素分布进行表征分析,并绘制了氧化动力学曲线。结果表明:DD33在1000℃下为完全抗氧化级,其氧化动力学遵循幂函数规律。质量增长存在两个阶段,即质量快速增长以及稳态增长阶段。Al元素的选择性氧化对应着质量快速增加阶段,NiO的加厚以及尖晶石层的复杂氧化对应稳态增长阶段。最终的氧化膜分为三层,最外层为NiO,中间层为Cr、Ta、Ni、Co和Al的混合氧化物层,最里层为Al_(2)O_(3)层,在氧化层的下方还有一层贫Al的γ′贫化层。

The isothermal oxidation behaviors of nickel base single crystal superalloy DD33 at 1000℃was studied.The phase composition,morphology,structural characteristics and element distribution of the ox⁃ide film were characterized and analyzed by scanning electron microscope,energy spectrum,X-ray diffractometer,electron probe X-ray microanalyzer,and the oxidation kinetic curve was drawn.The re⁃sults show that the oxidation kinetics follow the law of power function,and DD33 exhibits complete oxida⁃tion resistance at 1000℃.There are two stages of mass growth:rapid mass growth and steady mass growth.The selective oxidation of Al element corresponds to the stage of rapid mass growth.Thickening of NiO and complex oxidation of spinel layer correspond to the stage of steady mass growth.The final oxide film can be divided into three layers,the outermost layer is NiO,the middle layer is a mixed oxide layer of Cr,Ta,Ni,Co and Al,and the innermost layer is Al_(2)O_(3).There is an Al depletedγ′layer below the oxide layer.