Creep characterisation of Inconel 718 lattice metamaterials manufactured by laser powder bed fusion

Lattice metamaterials manufactured by laser powder bed fusion (LPBF) are limited by their performance for critical applications. The LPBF materials have microstructural or macroscale anomalies, such as suboptimal grain size, morphology, and lack of fusion. This results in LPBF metamaterials performance degradation for various mechanical properties, such as creep, which has seldom been researched. To understand the creep behaviour of LPBF Inconel 718, Body Centred Cubic (BCC) metamaterials were fabricated for creep test at 650 °C. Kachanov’s damage modelling has been used to predict the creep performance of the metamaterials under different loading conditions. Microstructural characterisation has been performed with Scanning Electron Microscopy (SEM) to identify critical microstructure defects affecting the failure mechanisms and creep behaviour s of the metamaterials. The results show that the loading conditions affect the fracture process of the metamaterials owing to different failure mechanisms. The simulation and test results show that the logarithmic decline in creep life when loading increases; also, logarithmic increase in the creep life when relative density increases. This article is protected by copyright. All rights reserved.