Deformation mechanisms in nanocrystalline palladium at large strains

• Published in: Acta materialia Vol. 57; no. 11; pp. 3391 - 3401
• Main Authors: Ivanisenko, Yu, Kurmanaeva, L., Weissmueller, J., Yang, K., Markmann, J., Rösner, H., Scherer, T., Fecht, H.-J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2009; Elsevier
• Subjects: Applied sciences; Dislocation slip; Exact sciences and technology; High-pressure torsion; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nanocrystalline; Plasticity; Twinning; Twinning; Dislocation slip; Plasticity; High-pressure torsion; Nanocrystalline; Deformation; Slip; Mechanical properties; Palladium; Mechanism; Dislocation; Torsion; Nanocrystal
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2009.03.049

The mechanical behaviour and microstructure evolution of nanocrystalline palladium was investigated. Material with an initial grain size ∼10 nm was prepared by inert gas condensation. Instrumented high-pressure torsion straining was used to characterize the flow stress during plastic deformation to shear strains up to 300. A change in primary deformation mechanism was induced by stress-induced grain growth. For grain sizes <40 nm, grain boundary mediated processes (shear banding, grain boundary sliding and grain rotation) controlled the deformation, with dislocation slip, twinning, and grain boundary diffusion providing the accommodation. For larger grain sizes, the operative deformation mechanism was dislocation slip.