November 2023 Volume 5

FORGING RESEARCH

the Earth’s mantle and a shop floor may seem far afield from one another, the conditions driving rock flow in the mantle and metal flow in a forging die are quite similar. Both processes see extreme thermomechanical loading with the only differences being the pressures involved (the pressures are about an order of magnitude lower during forging) and the deformation rates (deformation rates are 2 to 4 magnitudes higher during forging). For the efforts of this FIERF microgrant project, we focused on adapting multi-anvils designed for rock flow to manufacturing pressures by creating larger area anvils to spread the loading from the hydraulic press. To begin developing tools to watch material evolution during conditions simulating forging, experiments were performed at the X-ray Powder Diffraction (XPD) beamline at NSLS-II. These experiments consisted of initiating recrystallization and grain growth of Fe at high pressures (1-2 GPa) within a hydraulic multi anvil press, while the specimens were illuminated by a synchrotron X-ray beam. The role of pressure on alloy microstructural evolution is relatively unknown in comparison to temperature. The high pressures found in a forge can increase the yield strength of an alloy while slowing microstructural evolution, but quantitative measurements are limited. In the measurements performed at NSLS-II, the recrystallization process at pressure was tracked by continuously monitoring the evolution of scattered X-rays from the Fe samples on a large-panel X-ray detector sitting behind the specimen. Beyond demonstrating the feasibility of using multi anvil presses to interrogate metal evolution, pressure was found to significantly slow (4X) the kinetics of recrystallization and grain growth in the Fe specimens tested. A manuscript preprint describing the experiments is available online (https://arxiv.org/abs/2307.14478).

Critically, the FIERF microgrant supported the involvement of an undergraduate at Penn State, Lukas Kissell, to gain interest in alloy manufacturing and metals research through helping perform these experiments and data analysis. In addition, the FIERF microgrant is an important seed for a larger research program. Plans are currently underway to extend these capabilities to more complex loading conditions, higher deformation rates, and industrially-relevant alloy systems.

Darren C. Pagan Assistant Professor Materials Science and Engineering, Penn State Lukas A. Kissell Student Materials Science and Engineering, Penn State

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The undergraduate supported by the FIERF microgrant, Lukas Kissell, and NSLS-II staff scientist, Dr. Matthew Whitaker, mounting a Fe specimen contained within a multi-anvil assembly at the National Synchrotron Light Source II.

Contact Tricia Abruzzino for more information at tricia@forging.org

FIA MAGAZINE | NOVEMBER 2023 81