On Friday, 4th of October, Jorge Valilla will present his FYA entitled “Physical and thermodynamic simulation of Functionally Graded Materials”.
It will be a fully remote (zoom) event, at 4:30 pm:
With the up and coming interest for additive manufacturing (AM) of metallic materials and all its benefits, several techniques have evolved up to the point of enabling new routes for manufacturing materials tailor made for specific needs. That is the case of direct energy deposition (DED) manufacturing and its features suited for making functionally graded materials (FGMs).These kinds of materials show a gradual change in composition from one material to the other, coming as a great option when dealing with dissimilar joints or for location-specific properties in a bulk part. However, it is not without flaws, since apart from AM related defects, challenges related to these structures arise, such as property mismatches or formation of unexpected phases, which have to be addressed.
This thesis falls within the scope of a national (”Retos de Colaboracion
2019”) consortium with ArcelorMittal and AIMEN Technology Centre, called Multi-FAM (”Development of 3D multi-material and multi-functional parts through AM assisted by intelligent material and process design”), which aims to manufacture 3D printed multi-material parts for specific industrial needs. IMDEA intervenes in the material selection and design by developing tools to assess material compatibility between the two alloy systems selected (AISI SS316L and Inconel 718).
To do so, within the thesis, we combine computational thermodynamic
simulations, physical simulations, and advanced characterization.
In particular, thermodynamic simulations have been done based on the CalPHaD (Calculation of Phase Diagrams) methodology to calculate phases
fraction and their presence in the FGM gradient compositions.
Physical simulations were made by using a Gleeble 3800 simulator to join both alloys, obtaining a sound joint with a characteristic microstructure. In parallel, DED printed samples of sharp transitions between both alloys were manufactured and submitted to subsize tensile tests, showing mixed results and rupture morphologies.
This work presents a review of the state-of-the-art of FGMs, addressing their challenges and case studies, description of the methods and results to date, and a detailed look to future perspectives.