NONDIFFERENTIAL CONDUCTION CALORIMETER, A TOOL TO STUDY THE AFTER QUENCH BEHAVIOR IN SHAPE-MEMORY ALLOYS

After the development of differential conduction calorimeters realized by E. Calvet around 1946, the standard equipment always used a differ ential configuration. In home made systems for special purposes, the i nstrumentation available nowadays suggests that it is possible to use non-differential conduction calorimeters. In order to prove this, a si mple and cheap design was constructed and tested. A sensitivity of 700 mV/W near 298 K (in agreement with the detecting semiconductors), a n oise around 0.3 mu W and a long time fluctuation of the base line lowe r than 1 mu W were obtained. The reliability of the system was evaluat ed by analyzing the changes of single crystals of Cu-Zn-Al Shape Memor y Alloys after different thermal treatments. The calorimeter allowed t he: determination of a reproducible set of time constants related to t he heat treatments and to the mass (or shape) of the sample. It is con cluded that the experimental configuration used is suitable for this i sothermal analysis.