[Description: Fig. 4]
Heavy plastic deformation may refine grains of metals and make them very strong. But the strain-induced refinement saturates at large strains, forming three-dimensional ultrafine-grained (3D UFG) structures with random orientations. Further refinement of this microstructure is limited because of the enhanced mobility of grain boundaries. Very-high-rate shear deformation with high strain gradients was applied in the top surface layer of bulk nickel, where a 2D nanometer-scale laminated structure was induced. The strongly textured nanolaminated structure (average lamellar thickness of 20 nanometers) with low-angle boundaries among the lamellae is ultrahard and ultrastable: It exhibits a hardness of 6.4 gigapascal—which is higher than any reported hardness of the UFG nickel—and a coarsening temperature of 40 kelvin above that in UFG nickel.
Feed: Science: Current Issue
Posted on: Friday, 18 October 2013 11:00 AM
Author: X. C. Liu
Subject: [Report] Strain-Induced Ultrahard and Ultrastable Nanolaminated Structure in Nickel
Heavy shearing can produce a stronger, more thermally robust nickel microstructure. [Also see Perspective by Ramtani] Authors: X. C. Liu, H. W. Zhang, K. Lu
View article...<http://www.sciencemag.org/content/342/6156/337.summary?rss=1>
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