Grain Boundary Character Distributions in Nanocrystalline Metals Produced by Different Processing Routes

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 47; no. 3; pp. 1389 - 1403
• Main Authors: Bober, David B., Khalajhedayati, Amirhossein, Kumar, Mukul, Rupert, Timothy J.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2016; Springer Nature B.V
• Subjects: Alloys; Ball milling; Boundaries; Characterization and Evaluation of Materials; Chemistry and Materials Science; Deposition; Grain boundaries; Grain size; Materials Science; Metallic Materials; Metallurgy; Metals; Nanocrystals; Nanotechnology; Nickel base alloys; Structural Materials; Surfaces and Interfaces; Thin Films; Equal Channel Angular Pressing; Accumulative Roll Bonding; Annealing Twin; Coincident Site Lattice; Severe Plastic Deformation
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-015-3274-9

Nanocrystalline materials are defined by their fine grain size, but details of the grain boundary character distribution should also be important. Grain boundary character distributions are reported for ball-milled, sputter-deposited, and electrodeposited Ni and Ni-based alloys, all with average grain sizes of ~20 nm, to study the influence of processing route. The two deposited materials had nearly identical grain boundary character distributions, both marked by a Σ3 length percentage of 23 to 25 pct. In contrast, the ball-milled material had only 3 pct Σ3-type grain boundaries and a large fraction of low-angle boundaries (16 pct), with the remainder being predominantly random high angle (73 pct). These grain boundary character measurements are connected to the physical events that control their respective processing routes. Consequences for material properties are also discussed with a focus on nanocrystalline corrosion. As a whole, the results presented here show that grain boundary character distribution, which has often been overlooked in nanocrystalline metals, can vary significantly and influence material properties in profound ways.