Microstructures and mechanical properties of β-NiAlHf coated single crystal superalloy

作者：Gong, Xueyuan; Yang, Yonghong; Ma, Yue; Peng, Hui; Guo, Hongbo^*

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2016, 673: 39-46.

DOI：10.1016/j.msea.2016.07.067

• A. Electron microscopy
• A. Hardness measurement
• B. Nickel based superalloys
• D. Fracture
• D. Interfaces

A beta-NiAlHf coating was deposited by electron beam physical vapor deposition (EB-PVD) onto single crystal (SC) superalloy substrate. The microstructure evolution of the NiAlHf coating after annealing at 1100 degrees C was investigated and the mechanical properties of the coated substrate were also concerned. The crack initiation and propagation behavior of the coated substrate during three-point bending was studied. An interdiffusion zone (IDZ) was formed between the coating and substrate and the hardness of the precipitates in the IDZ layer was relatively higher than that of the coating and the substrate. The annealed specimen during bending revealed different crack initiation and propagation behavior from the uncoated specimen. Cracks were initiated at the carbides in the uncoated alloy. For the coated specimen after 10 h annealing, cracks were initiated mostly in the IDZ layer, due to the presence of mu-TCP phases. For the coated specimen after 50 h annealing, cracks were generated at the top of triangle-shaped gamma '-Ni3Al phases where stress concentration occurred, which finally propagated into the substrate, leading to the reduction of the alloy in strength.

• 出版日期2016-9-15
• 单位西安航天动力研究所; 北京航空航天大学