DLC被覆処理を施したTi-6Al-4V合金の疲労特性

概要

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This study was conducted to investigate the effect of DLC (diamond-like carbon) coating and a hybrid surface modification composed of plasma carburizing and DLC coating on the fatigue properties of Ti〜6Al-4V alloy. In the hybrid surface modification, plasma carburizing at the first stage was conducted to generate a hardened layer for suppressing plastic deformation which can occur under the DLC layer. The results of tensile test showed that the static strengths of both the DLC coated material and the hybrid surface-modified material were maintained because growth of microstructure in the substrate during the plasma carburizing and DLC coating was unremarkable. However, elongation of the hybrid surface-modified material was slightly decreased by cracking of the hardened layer. In the DLC-coated material, the DLC layer possessed a high adhesion so that it effectively suppressed fatigue crack initiation from the surface and the fatigue strength was improved by 10%. On the other hand, the adhesion of the DLC layer in the hybrid surface-modified material was lower than half of the adhesion in the DLC-coated material. Therefore, although the fatigue strength was improved by the hybrid surface modification, it was lower than the case of the DLC-coated material.
一般社団法人日本機械学会の論文
2008-05-25