Influence of Precracked Diffusion Coating of Pt-Modified Aluminide on HCF Fracture Mechanism of IN 792 Nickel-Based Superalloy
High-cycle-fatigue (HCF) fracture mechanism of nickel-based superalloy IN 792 coated with Ptmodified aluminide outward-diffusion coating is studied with focus on the influence of coating cracks. It is found that cracking of the diffusion coating prior to HCF tests has little influence on the fatigue limit of specimens with thin coating (50 μrn) but lowers the fatigue limit of specimens with thick coating (70 μm). By fractographic analysis, three types of fractural modes are established according to their crack initiations: internal, external and mixed. While external fractural mode is related to the propagation of existing cracks in the coating, internal facture initiates often at Ti-Ta-W-rich carbides and/or topological-closepacked (TCP) phases and grainboundaries in the superalloy. Increasing the thickness of diffusion coating or the amplitude stress promotes the fractural mode transition from internal/mixed to external. The influence of precracking of coatings on the HCF fracture mechanism can be qualitatively explained by its influence on the stress intensity factor.
Diffusion coating Nickel-based superalloy HCF Fracture mechanism
Kang Yuan Ru Lin Peng Xin-Hai Li Sten Johansson
Department of Management and Engineering, Linkoeping University, SE-58183 Linkoeping, Sweden Siemens Industrial Turbomachinery AB, SE-61283 Finspang, Sweden
国际会议
大连
英文
24-29
2011-10-19（万方平台首次上网日期，不代表论文的发表时间）