Non-differential conduction calorimeter, a tool to study the after quench behaviour in shape memory alloys

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