First DTA tests were carried out with CuSn alloys to be certain that the protocol of investigation works and the alloy to be studied is not going to contaminate the DTA. For the analyses, a NETZSCH DSC 404C was used. The alloys (CuAs with 3, 4, and 5 wt.% As) were sealed in tantalum crucibles in Ar atmosphere. First cooling rates were fixed at 2, 5, 10, and 20 K/min. With the selected alloys we still remain in the range of the Cu based alpha solid solution. With the 2K/min cooling rate no eutectic transformation was noticed, which is coherent with the equilibrium phase diagram. 4 and 5 wt% As show already at 5K/min and 10K/min signs of eutectic transformation, which happens at lower temperature than in the phase diagram. The measurements at 20K/min are missing for CuAs-3 and will be re-measured. The measurements for the alloys with 1, 2, 6, and 7 wt.% As are currently carried out. Further analyses are planned with 8, 11, and 19 wt.% As, in order to achieve a complete set of data to draw the liquidus curve and the interception with the eutectic line.