Research Projects

The proposed project aims to address the intricate machining challenges associated with Cold Spray (CS) deposits, by developing a systematic framework that integrates experimental and computational approaches. CS deposits possess unique microstructural features, such as porosity, strain hardening, splat morphology, grain size and weak inter-splat adhesion strength (IAS), which contribute to machining difficulties like irregular chip formation, splat peel-off, and consequently compromised surface integrity. This project focuses on advancing the machinability understanding of these materials, contributing to their broader industrial applicability. The foundation of the research lies in exploring how the CS deposit characteristics affect their machining behaviour. To investigate this, SS316 deposits will be fabricated using a co-axial laser-assisted cold spray (COLA-CS) system under varying parameters. These deposits will undergo detailed characterization using EBSD and SEM to reveal deposit characteristics, which serve as the basis for correlating material properties with machining outcomes. Orthogonal machining experiments will form the core of the study, offering insights into the cutting mechanics of CS deposits. By analyzing chip formation, and temperature fields during machining, the project will identify deformation mechanisms, including intra-splat shearing and inter-splat boundary failures. Post-machining microscopic evaluations will further investigate surface and subsurface integrity, linking machining outcomes to the microstructural characteristics of the deposits. Experimental studies, though essential, cannot fully reveal stress-strain evolution during machining. To address this, a robust FEM model will be developed using material properties validated through Split-Hopkinson Pressure Bar (SHPB) tests and machining experiments on formed SS316 specimens mimicking CS-like strain hardening and recrystallization. Iterative IAS refinement and simulations will enable the FEM model to accurately depict machining mechanics, offering insights into stress-strain evolution and material deformation. To overcome machining challenges, strategies such as laser-assisted machining (LAM) and laser-assisted burnishing (LAB) will be employed. LAM aims to relax strain and reduce cutting forces by preheating the material, promoting smoother chip formation and minimizing subsurface damage. LAB aims to smooth post-machining surface flaws by redistributing laser-softened material by deformation. Together, these techniques will enhance surface integrity and machining outcomes, addressing both intra-splat and inter-splat failure mechanisms. In summary, this project combines microstructural analysis, machining experiments, FEM simulations, and advanced techniques to enhance CS deposit machinability, advancing machining processes and expanding CS technology's industrial use.