Instytut Podstawowych Problemów Techniki

UMO-2023/51/B/ST8/01751

2024-08-06 / 2028-08-05

jedyny wykonawca

NCN

OPUS

26

The aim of this project is to develop knowledge and provide solutions for unresolved challenges in additive manufacturing (AM) to enable faster and wider adoption of AM by different sectors such as aerospace, healthcare, energy, automotive, defence, railway, and other emerging sectors. In this project, combined experimental and numerical approaches to investigate the initial and subsequent yield surfaces of Inconel 718, Inconel 625 and Ti5553 manufactured by using Laser Engineering Net Shaping (LENS) technology subjected to multiaxial loading are proposed. Understanding the effects of defects and anisotropy in microstructure and mechanical properties of AM materials subjected to multiaxial stress state will enable comprehensive knowledge of the process–microstructure–property–performance relations of AM materials. This new understanding will accelerate the technology readiness level for certification and qualification of AM technologies and unleash their potential for different industrial applications. The proposed project is devoted to the mechanical and fracture characterization of AM materials, specifically Inconel 718, Inconel 625 and Ti5553. The AM allows to design a process flow in the more flexible manner, which take into account the functionality of the components. The objective of the research is to study the main physical mechanisms responsible for the plastic deformation resulting from the complex mechanical loadings. The process of initiation and subsequent propagation of micro-cracks from inherent defects in the AM materials will be also analyzed. It is known, that the AM properties are strong functions of the printing strategy and process parameters applied. Characterization and modelling have the potential to study the interrelationship between them. A key question is how AM process parameters affect microscopic plastic mechanisms controlling the evolution of defect leading toward the state of advanced yielding? The materials will be tested in the as-built state and after prior deformation due to monotonic or cyclic loadings. The yield surface concept will be used to identify an initial texture of the tested materials and subsequent modifications of their properties by its evolution due to the loading history induced. The material in the as-built state for cylindrical specimens will have the form of a tube. The same materials for cruciform specimens will have the form of a plate. Basic research will be preceded by preliminary tests that will provide results necessary to determine the basic mechanical properties of AM materials. Also microstructural analysis is planned to be performed using scanning microscopy. The proposal also deals with development of original experimental techniques for materials characterization under complex stress states using thin-walled tubular and cruciform specimens. A novelty in this area will be an application of the unique testing stands including Instron 1343 enabling simultaneous loading of thin-walled tubular specimens by the axial force, twisting moment and internal pressure; and Instron 8800 Biaxial Testing Machine for tests on the cruciform specimens, which is the first such machine in Poland. All experiments will be supported by Digital Image Correlation. The results coming from tests on cylindrical specimens and cruciform ones carried out for the AM materials within a single project are very unique, and with regard to our knowledge are not available in the scientific publications up to now. It has to emphasised that for the advanced verification of the yield criteria the results of such combinations of experiment are extremely valuable. The last important aim of the project is related to modelling of the deformation mechanisms and degradation processes associated with the local stress-strain evolution. Finite element method (FEM) will be used to simulate the low-cycle behaviour of materials For the purpose of the project, the following objectives have been identified: • Establishing a robust design, fabrication, characterization, and experimental framework for the development of 3D stress state space for AM materials. • Investigating the effects of defects and anisotropy in AM materials on their yield and hardening characteristics. • Developing a numerical model capable of predicting the mechanical response of AM materials subjected to multiaxial loading.