211 デジタル画像相関法によるセラミックス遮熱コーティング材の高温疲労き裂開口変位計測

概要

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Fatigue tests were conducted at both 893K and room temperature for ZrO_2-8Y_2O_3-sprayed and Al_2O_3-sprayed type 304 stainless steels. Surface Crack Opening Displacement (COD) was measured using a digital image correlation method during the fatigue test to examine the fatigue process. In case of a ZrO_2-8Y_2O_3-sprayed specimen, the crack penetrated into a substrate through a bond-coating layer, while in case of an Al_2O_3-sprayed specimen, the crack retained at the interface between the bond-coating and the substrate and another crack which initiated at the delaminated interface penetrate into the substrate. The fatigue life of an Al_2O_3-sprayed specimen was longer than that of a ZrO_2-8Y_2O_3-sprayed specimen. The fatigue strength was obviously improved using a Low Pressure Plasma Sprayed (LPPS) bond-coating instead of a Atomospheric Plasma Spraying (APS) bond-coating. It was concluded that the improvement of fatigue life was caused by the restriction of a crack initiation into the substrate due to the LPPS bond-coating with a relatively higher strength.
一般社団法人日本機械学会の論文