Fatigue strength of TiN and TiCN ceramic coated 1Cr-1Mo-0.25V steel
- Kyungpook National Univ., Taegu (Korea, Republic of). Dept. of Mechanical Engineering
- Univ. of Tokusima (Japan). Dept. of Mechanical Engineering
- Korea Research Inst. of Standards and Science, Taejon (Korea, Republic of)
- POSTECH, Pohang (Korea, Republic of). Accelerator Lab.
In order to clarify the effect of a surface thickness of ceramic coating films on the fatigue strength, crack initiation and propagation of material, fatigue tests (R = {minus}1, R = 0.1) were carried out in room air, using the round plain specimens and compact tension (CT) specimens of 1Cr-1Mo-0.25V steel coated with TiN and TiCN by physical vapor deposition (PVD). The obvious improvement of fatigue life was confirmed in the ceramic coated specimens in the region of low fatigue strength, as compared with non-coated specimens. It was explained that the increase of fatigue life in the TiCN and TiN coated materials was attributed to the retardation of crack initiation due to the restriction of surface plastic deformation in the substrate with hard coating layer. Also, the fatigue strength at 10{sup 7} cycles of ceramic coated material was increased about 20% higher than that of non-coated base material. The fatigue crack of TiCN and TiN coated material was mainly initiated at the inclusions of Al compositions near the substrate under the coating film. And the experimental results are evaluated by the Paris equation, da/dN = C(K){sup m}, where the crack growth rate of coated specimens are equivalent to that of the non-coated specimen regardless of coating thickness and specimen thickness.
- OSTI ID:
- 293094
- Report Number(s):
- CONF-970980--; ISBN 0-87339-382-1
- Country of Publication:
- United States
- Language:
- English
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