Residual stress and mechanical properties analysis of TC4 alloy fabricated by laser additive manufacturing

Large residual stresses would be generated in the laser additive manufactured (LAMed) structures after processing rapid and intense heating and cooling cycles with bad mechanical properties. Scholars have tried many methods to decrease the residual stress to prevent the structures from being broken and improve the mechanical properties. In this study, residual stress and mechanical properties of LAMed structures are analyzed, and the advanced measuring method, laser ultrasonic technique, is used to detect the residual stresses accumulated in the samples in time. The results show that when the solution temperature is less than T beta (992 degrees C), the residual stress increases gradually with the increase of solution temperature, and when the temperature is more than T beta (992 degrees C), Widmanst & auml;tten structure will significantly reduce the residual stress; the mechanical properties of the specimen decrease with the increase of the solution temperature, and the different cooling methods do not have much effect on the elastic properties of the specimen. Considering the residual stress and mechanical properties, the HT1 system used in this paper is the best. This study is of great significance for the reasonable suppression of residual stress and the regulation of mechanical properties of TC4 titanium alloy fabricated by laser additive manufacturing.