Bending and Torsion Fatigue of Inconel 713LC with and withouth Diffusion Coating

Bending and Torsion Fatigue of Inconel 713LC with and withouth Diffusion Coating

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Experimental results of low-cycle fatigue loading of cylindrical specimens made of the cast nickel-based superalloy, Inconel 713LC, that were prepared with and without the diffusion aluminide coating are presented in the paper. Specimens were subjected to symmetrical bending and torsion loadings with the sine shape of the loading cycle of frequency f = 30 Hz under the load-control regime. Experiments were carried out at room temperature in the laboratory air environment by means of the testing stand MZGS-200 of the polish provenance up to a final rupture. In the case of bending loading, the diffusion coating leads to a decrease of the fatigue life. Conversely, the presence of the coating improves the fatigue performance in the case of the torsional loading. Fracture surfaces of selected specimens were observed in the scanning electron microscope. Fractographical analysis revealed that the different bending and torsion fatigue behaviour was mainly caused by different initiation mechanisms. An accelerated crack initiation took place at the carbide/matrix interface within the inner sub-layer of the diffusion coating during the bending loading due to a high tensile stress component on the specimen surface. On the other hand, the crack initiation was not influenced by carbides in the case of torsion loading where the tensile stress components were negligible.

Experimental results of low-cycle fatigue loading of cylindrical specimens made of the cast nickel-based superalloy, Inconel 713LC, that were prepared with and without the diffusion aluminide coating are presented in the paper. Specimens were subjected to symmetrical bending and torsion loadings with the sine shape of the loading cycle of frequency f = 30 Hz under the load-control regime. Experiments were carried out at room temperature in the laboratory air environment by means of the testing stand MZGS-200 of the polish provenance up to a final rupture. In the case of bending loading, the diffusion coating leads to a decrease of the fatigue life. Conversely, the presence of the coating improves the fatigue performance in the case of the torsional loading. Fracture surfaces of selected specimens were observed in the scanning electron microscope. Fractographical analysis revealed that the different bending and torsion fatigue behaviour was mainly caused by different initiation mechanisms. An accelerated crack initiation took place at the carbide/matrix interface within the inner sub-layer of the diffusion coating during the bending loading due to a high tensile stress component on the specimen surface. On the other hand, the crack initiation was not influenced by carbides in the case of torsion loading where the tensile stress components were negligible.

fatigue, bending, torsion, Inconel 713LC, diffusion coating

fatigue, bending, torsion, Inconel 713LC, diffusion coating

SLÁMEČKA, K.; BONAVENTUROVÁ, K.; POKLUDA, J.

2012

18.05.2011

Tanger sro

Ostrava

978-80-87294-24-6

METAL 2011 Conference Proceedings

Metal

692

697

6