High temperature creep property of a novel porous double layer cooling structure for gas turbine blades

Abstract

This article investigates the high-temperature creep macroscopic and microscopic fracture mechanism of the porous double layer (PDL) cooling structure through experiments, and predicts the creep life of the structure using the back propagation (BP) neural network model based on the bone point stress method. The high temperature creep fracture of the PDL cooling structure is determined by the macro structure characteristics and the microstructure properties. Impingement holes and effusion holes, as stress concentration region, provide a place for crack initiation. The crack growth rate of effusion plate is greater than that of impingement plate. When the creep crack extends to a certain length, the effusion plate breaks first, and then the impingement plate breaks instantaneously. At the interface between carbide and matrix, microcracks are prone to occur due to stress concentration and inconsistent deformation, thereby promoting the initiation and propagation of macroscopic cracks. The BP neural network model based on the bone point method has a good prediction result for the creep life of the PDL cooling structure, and the maximum prediction error is 9%.