Application of Laser Technique on the Formation of Superconductive Layer on the Bulk of Press Formed Bi System - Evaluation of Mechanical Properties of the Treated Bulk

In the study of the application of a laser technique on the bulk of press formed Bi system, the authors have reported that a superconductive layer can be obtained underneath the laser melted layer. In a continuing series of this study, this paper deals with the mechanical properties of the bulk laser treated. Superconductive powder of Bi system, 2223 phase was pressed to form a disk specimen of 2 mm thick and 10 mm at 29 MPa to 196 MPa. Then a CO2 laser beam of output power 6 W to 9 W was scanned linearly in air to melt the surface of the specimen to be subjected to the evaluation of hardness and fracture strength. The experimental results showed that the values of microvickers hardness of superconductive layer and melted layer are 135 and 105 respectively while that of the specimen as press formed is as low as 45. The fracture strength of the laser treated specimen was increased to 34 N from 15 N. The mechanical properties obtained deserve non sensitive handling in a practical use of the treated bulk.