研究論文
TiAlNコーティングを施したTiAl合金の高温疲労強度に及ぼす膜厚の影響
2005 年 55 巻 2 号 p. 91-96
詳細
2005 年 55 巻 2 号 p. 91-96
The fatigue strength of TiAl intermetallic alloy coated with TiAlN film was studied in vacuum at 1073 K using a SEM-servo testing machine. In addition, three kinds of TiAlN films were given by physical vapor deposition (1,3 and 10 μm). The fatigue strength of 3 μm was highest. Also, the fatigue strength of 1 μm was lowest. From this result, existence of optimum film thickness was suggested because the difference of fatigue strength arose in each film thickness. The justification for existence of optimum film thickness is competition of 45-degree crack and 90-degree crack. The 45-degree crack is phenomenon seen in the thin film (1 μm), and is caused by plastic deformation of TiAl substrate. The 45-degree crack is the factor of the fatigue strength fall by the side of thin film. In contrast, the 90-degree crack is phenomenon in the thick film (10 μm), and is caused as result of reaction against load to film. The 90-degree crack is the factor of the fatigue strength fall by the side of thick film. In conclusion, the optimum film thickness can perform meso fracture control, and improves fatigue strength.
