Abstract

Friction Stir Processing (FSP) has been investigated as a means of microstructural modification aimed at improving mechanical properties such as corrosion resistance and wear resistance of biomedical-grade cobalt-chromium-molybdenum (CoCrMo) alloy. FSP was successfully completed on high-carbon ASTM F1537 CoCrMo plates with operating temperatures ranging from 630°C to 850°C by adjusting spindle speed, traverse speed, and forge force. Hardness, wear resistance, and corrosion resistance testing were performed, along with Electron Backscatter Diffraction (EBSD) to analyze grain refinement and phase structure. FSP produced grain refinement up to 97% relative to the untreated baseline across the investigated temperature range, with lower processing temperatures yielding finer, more refined microstructures. The best resulting wear resistance of the treated CoCrMo was reduced by approximately one order of magnitude compared to the unprocessed alloy under the optimal single-pass conditions, and the corrosion rate was reduced by up to 86% in the best-performing processed condition, pointing toward FSP as a viable surface modification strategy for improving the in-vivo performance of biomedical implants. A finite-element-based FORGENxT® simulation was developed and validated to predict thermal histories, establishing a computational framework for guiding future parameter selection.

Degree

College and Department

Ira A. Fulton College of Engineering; Manufacturing Engineering

Rights

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