Effect of content on the macro-defect structure of melt processed superconductor
E Sudhakar Reddy; T Rajasekharan; E Sudhakar Reddy; Defence Metallurgical Research Laboratory, PO Kanchanbagh, Hyderabad 500 258, India; T Rajasekharan; Defence Metallurgical Research Laboratory, PO Kanchanbagh, Hyderabad 500 258, India
Журнал:
Superconductor Science and Technology
Дата:
1998-02-01
Аннотация:
Applications of superconducting material demand materials with minimized macro-structural defects like cracks, voids and pores. Such defects affect the current density values attainable and also preclude shaping the material into useful components. In order to study and minimize the above defects, we have melt processed with systematically increasing amounts of (211) as reinforcement. It is observed that practically all the shrinkage associated with melt processing occurs at the melting stage and not at the texturing stage. The variation of shrinkage as well as the size of pores residual in the samples with the increasing 211 content can be correlated to the size of the 211 particles in the pro-peritectic liquid at . Macro-cracks, parallel to the intrinsic micro-cracks between the 123 platelets, are observed in all the domains. The number and nature of these cracks are independent of the 211 content. The origin of these cracks is discussed.
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