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Microstructural evolution and strength variability in microwires

Agepati, S and Ghosh, P and Chokshi, AH (2016) Microstructural evolution and strength variability in microwires. In: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 652 . pp. 239-249.

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Official URL: http://dx.doi.org/10.1016/j.msea.2015.11.086

Abstract

Tensile experiments on cold-drawn Ni microwires with diameters from similar to 115 to 50 gm revealed high strengths, with significant strength variability for finer wires with diameters less than similar to 50 gm. The wires showed pronounced necking at fracture. The coarser wires with diameters > 50 mu m exhibited conventional ductile cup-cone fracture, with dimples in the central zone and peripheral shear lips, whereas finer wires failed by shear with knife or chisel-edge fractures. Shear bands were observed in all samples. Further, through- section microscopy of selected fractured samples revealed that the shear bands did not go across the enitre specimen for the coarser wires. The shear bands led to grain fragmention, with a reduction in grain aspect ratio as well as rotations away from the initial < 111 > orientations. The strength data were analysed based on a Weibull approach. The data could be rationalized in terms of failure from volume defects in coarser wires, with a high Weibull modulus, and from surface defects in finer wires, with a low Weibull modulus and greater variability. (C) 2015 Elsevier B.V. All rights reserved.

Item Type: Journal Article
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Additional Information: Copy right for this article belongs to the ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Keywords: Microwires; Shear band; Strength; Fracture; Weibull
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 03 Mar 2016 05:34
Last Modified: 03 Mar 2016 05:34
URI: http://eprints.iisc.ernet.in/id/eprint/53362

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