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Published 1986 | public
Book Section - Chapter

Microstructural Characteristics of a Shock-Consolidated Glass-Forming Alloy Powder

Abstract

An irregularly shaped, microcrystalline Markomet 1064 alloy powder (Ni_(55.8)Mo_(25.7)Cr_(9.7)B_(8.8), ~50 µm diameter) was consolidated by plane shock waves with energies ranging between 210 and 595 kJ/kg. The recovered compacts were analyzed to determine structural changes which occurred within the particles (due to deformation), and at particle boundaries (due to deformation and localized melting). The crystalline regions of the particles exhibit deformation twins, with dislocation networks and tangles within individual crystals (grain size ~0.4 µm). Localization of plastic strain along shear bands was also observed in the interior of the particles. Recrystallization of some of the heavily deformed grains occurred near the interface between unmelted particle interiors and melted particle surfaces. The melted and rapidly solidified interparticle regions were confirmed to be amorphous. Large Mo-rich precipitates (0.15 µm diameter) present in the annealed powder, were not melted and remained as isolated particles in the amorphous regions of the compact. A dispersion of fine spherical Cr- rich amorphous phase (~0.03 µm diameter) was observed randomly distributed in tile amorphous material. Nucleation and growth of fine crystallites occurs in some of these spherical regions.

Additional Information

© 1986 M. Dekker. This research was supported by the National Science Foundation under grant No. DMR-8315214 and the California Institute of Technology Program in Advanced Technologies. The authors wish to acknowledge the use of Professor Thomas J. Ahrens' 20 mm propellant gun facility in the Seismology Laboratory and the use of Professor Jean-Paul Revel's TEM/STEM system at the California Institute of Technology. The help of Mr. Patrick Koen in the TEM work is gratefully acknowledged.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023