Understanding microstructure heterogeneities to engineer novel alloys using additive manufacturing (26/08/25)
Speaker and Affliation:
Dr. Avinash Hariharan
Materials for Additive Manufacturing Steel Institute, RWTH Aachen, Germany
When?
26th August, 2025 (Tuesday), 3.00 PM (India Standard Time)
Where
KPA Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
Laser additive manufacturing of metals (LAM), also known as 3D printing, is a manufacturing technology to fabricate complex macroscale parts layer-by-layer using gas atomized powders. During the LAM process, alloys experience distinct thermal histories associated with the repeating melting-solidification and heating-cooling cycles. This complex processing condition results in steep temperature gradients and significantly high cooling rates. Such spatially variable thermal profile facilitates heterogeneities in the microstructure scale such as local variation in chemical composition, formation of locally dependent microstructures and phase transformation. These solidification conditions and the associated heterogeneities provide opportunities to design novel metallic alloy compositions along with novel microstructures. In addition, these complex thermal histories lead to the evolution of residual stresses and combined with heterogeneous chemical composition, leads to microscale defects such as solidification cracks. Understanding the physics of defect formation, chemical and microstructure evolution is critical for alloy design, for and using, LAM. In this talk, I focus on 3 different material systems, nickel-base superalloys (for aerospace), beta-titanium alloys (for biomedical implants) and high-strength steels (for automobile applications) fabricated using LAM. The facets of microstructure evolution, multiscale chemical heterogeneity during LAM, and post-LAM heat treatments will be discussed. Additionally, a strategy to use laser-based techniques for high-throughput alloy design, and surface functionalization strategies will also be discussed.