涂层扩散热处理工艺对DD6单晶高温合金组织和力学性能的影响

Effect of Coating Diffusion Heat Treatment Process on Microstructure and Mechanical Property of the DD6 Single Crystal Superalloy

研究了870℃/6h涂层扩散热处理工艺对第二代镍基DD6单晶高温合金(简称DD6合金)组织和性能的影响。研究结果表明,采用870℃/6h涂层扩散热处理工艺处理后,DD6合金的显微组织、760℃拉伸性能、980℃/250MPa持久性能、700℃高周疲劳性能无明显变化。DD6合金760℃拉伸断裂类型为准解理断裂,980℃/250MPa持久断裂类型为韧窝断裂,700℃高周疲劳断裂类型为准解理断裂。涂层扩散处理没有改变DD6合金的断裂机制。

The effect of coating diffusion heat treatment process of 870 ℃/6 h on microstructure and mechanical property of a second generation nickel-based DD6 single crystal superalloy (DD6 alloy for short) has been investigated. The results indicates that the DD6 alloy shows no obvious change on the microstructure, tensile properties at 760 ℃, stress rupture properties at 980 ℃/250 MPa and high cycle fatigue (HCF) properties at 700 ℃ after the coating diffusion heat treatment of 870 ℃/6 h. The tensile fracture mechanism of the alloy at 760 ℃ is quasi-cleavage fracture. The stress rupture mechanism at 980 ℃/250 MPa is dimple mode. The HCF fracture mechanism at 700 ℃ is quasi-cleavage fracture. The fracture mechanisms of the DD6 alloy aren’t changed by coating diffusion treatment.