Dr. Anthony D. Rollett, Carnegie Mellon University
Rapid advances in 3D printing of metals have enabled widespread used in industry. Key questions remain as to how to qualify printers and certify parts, especially in terms of defect structures. Under support from the NASA-ULI program, a multi-university team is determining process windows, characterizing defect structures, microstructures & surface finish, and measuring fatigue resistance in 4-point bend fatigue. Preliminary results point to similar process windows for the same model at different locations when using a consistent source of Ti-6Al-4V powder. Microstructure and basic mechanical properties can be predicted from thermal history albeit heuristically. Transferring the methodology to an aluminum alloy in a different printer, however, required re-evaluation of melt pool sizes, which is basic to the proposed physics-based approach to qualification. The fatigue results reveal a strong dependence of life on defect content, as expected, which suggests a close connection to the process window for printing. Overall ICME needs include the need for computational tools that predict melt pool shape & size, melt pool stability, microstructure formation, including texture, diffusion, and solid state phase transformation. The ultimate aim is to predict the process window for a given material and printer.
About the speaker
Dr. Tony Rollett is the US Steel Professor in Materials Science & Engineering at Carnegie Mellon University where he has been since 1995. He was previously at the Los Alamos National Laboratory from 1979-1995. He is recipient of multiple awards including Fellow of TMS in 2011 and International Francqui Professor for 2020-2021 (Belgium). He is a co-Director of the NextManufacturing Center at CMU and is a leader in research & education in metals additive manufacturing and processing-microstructure-properties relationships.
DATE: Wednesday, December 8, 2021
6:30 pm Networking
7:00 pm Presentation
7:45 pm Q&A