ダイヤモンド被覆WC-Co超硬合金の疲労強度特性に及ぼす膜厚の影響

概要

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The diamond film by CVD method offers outstanding impact, fatigue and wear resistance relative to conventional coating film, ex., TiC, TiN film. For that reason, the diamond film on substrate attracts a large expectation in mechanical industry. In proceeding paper, we reported relationship between fatigue strength and microstructure of diamond coated WC-Co alloys with various CVD conditions. However, we have not investigated at the effect of film thickness on fatigue strength and another mechanical properties of this material. In this study, the mechanical properties of diamond film coated WC-Co alloys having a few thickness was discussed on the basis of bending fatigue test. The main results obtained in this work are as follows : (1) The fatigue property of diamond coated WC-Co alloy was essentially depended on the thickness of film. However, the influence of microstructures, i.e., phase transformation of Co phases near substrate surface and process of film growth appeared for the fatigue strength of this materials at film got thin. (2) In the finite element method, FEM, analysis, the stress concentration part differed by Young's modulus of thin film. In case of high Young's modulus, the stress concentration was occuring at surface in material, it had be moving into a interface with decreasing Young's modulus of the film.
社団法人日本機械学会の論文
1998-09-25