التفاصيل البيبلوغرافية
| العنوان: |
The influence of thermal precompression on the mechanical behaviour of Ag-sheathed (Bi,Pb)2223 tapes with different matrices |
| المؤلفون: |
Passerini, Reynald reynald.passerini@physics.unige.ch, Dhallé, Marc1, Giannini, Enrico1, Witz, Grégoire1, Seeber, Bernd1, Flükiger, René1 |
| المصدر: |
Physica C. Jul2002, Vol. 371 Issue 3, p173. 12p. |
| مصطلحات موضوعية: |
*CRITICAL currents, *STRAINS & stresses (Mechanics), *MECHANICAL properties of metals |
| مستخلص: |
The behaviour of the critical current in longitudinally strained Bi,Pb(2223) tapes shows a strain-insensitive plateau up to an irreversible strain limit ϵirr. For higher strains, the formation of cracks induces an abrupt decrease of the critical current. We investigate the relationship between precompression and irreversible strain limit with a set of tapes made with different filling factors as well as an in situ Inconel 600-reinforced tape. Ic(ϵ) curves were measured in a longitudinal strain apparatus at 77 K. The precompression at the measurement temperature is numerically estimated for each sample as well as the evolution of precompression during the cool-down. These calculated values are compared to the fracture susceptibility of extracted filaments, which gives an empirical estimate of the precompression. The main hypothesis of the “Irreversible Ic Reduction Model” is confirmed, i.e. the irreversible strain limit essentially depends on precompression. However, we also found that the regime where Ic remains constant contains a tensile component: the plateau extends beyond the external tensile strain needed to relieve the thermal precompression and includes a regime where the ceramic is further elongated non-destructively. This non-destructive deformation can be understood as a “connected-grains” behaviour, and extends the strain-insensitive plateau ∼0.1% beyond the precompression strain. This value is confirmed with a three points bending experiment performed on single filaments which gives a similar value for the bending failure strain. A comparable regime was found to exist also under compressive strain. These non-destructive regimes are of great importance for practical applications since up to a certain level the precompression can develop without any Ic degradation. [Copyright &y& Elsevier] |
| قاعدة البيانات: |
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