CUED Publications database

Characterisation of the mechanical failure and fracture mechanisms of single grain Y-Ba-Cu-O bulk superconductors

Congreve, JVJ and Shi, Y and Huang, KY and Dennis, AR and Durrell, JH and Cardwell, DA (2020) Characterisation of the mechanical failure and fracture mechanisms of single grain Y-Ba-Cu-O bulk superconductors. Superconductor Science and Technology, 33. ISSN 0953-2048

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Abstract

The widespread use of melt processed, single grain (RE)-Ba-Cu-O bulk superconductors [(RE)BCO], where RE = Y, Gd or Sm, is limited predominantly by the poor mechanical properties of these inherently brittle, ceramic-like materials. The high density of flaws, such as cracks and voids, within the single grain microstructure leads directly to a low fracture toughness. As a result, the Lorentz forces, generated when these materials carry current in the presence of a large magnetic field, create stresses sufficiently large to cause brittle failure. The addition of Ba-Cu-O (liquid phase) and Ag to the precursor composition prior to melt-growth has been demonstrated to be effective in improving the mechanical properties of these technologically important materials. In this work, we characterise the mechanical failure of single grain YBCO bulk superconductors in terms of a Weibull statistical distribution. In addition, differences in fracture mechanisms have been studied to provide a better understanding of how the provision of additional liquid phase and silver produces YBCO single grains with better resulting mechanical properties and how these can be improved further.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div C > Materials Engineering
Div C > Engineering Design
Depositing User: Unnamed user with email sms67@cam.ac.uk
Date Deposited: 19 Nov 2019 01:31
Last Modified: 09 Sep 2021 02:11
DOI: 10.1088/1361-6668/ab5b46