Strength Evaluation of Alumina Spray Coating (5th Report, Consideration of the Strength in Sprayed Structure under Thermal Stress)

Abstract

In this study, a fracture probability under a thermal stress distribution is calculated with a dangerous volume quantification method that was proposed in the former report. The fracture strength due to the thermal stress is calculated, based on the finite element method with the fracture temperature and the aluminum creep properties. The fracture strengths predicted with the proposed method are appropriate for the experimental results obtained by heat tests. The calculated dangerous volume intended for 90% of product in alumina spray coating on an aluminum layer is the part where a stress of 96% more than the maximum stress has been received. For the dangerous volume on thermal stress distribution, it is sufficient to consider an experienced dangerous volume in which the dangerous volume is a volume where a stress of 90% more than the maximum stress is loaded. It is shown that the fracture origin is located in the dangerous volume calculated by the present method and that the fracture strength predicted with a fracture origin size is almost equal to the fracture strength predicted by this study.