A solution for estimating high-temperature strength based on additive manufacturing characteristics

Abstract

Large sizes and destructive items hindered standard uniaxial testing for in-service parts manufactured by laser additive manufacturing (LAM). Therefore, small-scale testing techniques, such as small punch tensile (SPT) testing, were widely employed to assess local mechanical characteristics. In this study, layer-by-layer fabrication of Hastelloy X was produced via LAM-assisted ultrasonic micro forging treatment (UMFT). The microstructure and fracture of components showed that UMFT successfully reduced LAM defects; the defect distribution characteristics of the sample blocks and SPT specimens were determined by the extreme value method (EVM); the effect of defect characteristics on strength was evaluated by Pearson correlation coefficient (PCC); the SPT strength estimation models based on the LAM characteristics were proposed using the surface defect distributions of SPT specimens. The results of various error assessments showed that the proposed models had better accuracy and stability than the classical SPT models; based on the distribution of defects in LAM blocks, the total strength estimation error of LAM Hastelloy X was within 2%.