The reaction of Zr/B multilayers with a 50 nm modulation period has been studied using scanning AC nanocalorimetry at a heating rate of approximately 10(3) K/s. We describe a data reduction algorithm to determine the rate of heat released from the multilayer. Two different exothermic peaks are identified in the nanocalorimetry signal: a shallow peak at low temperature (200-650 degrees C) and a sharp peak at elevated temperature (650-800 degrees C). TEM observation shows that the first peak corresponds to heterogeneous inter-diffusion and amorphization of Zr and B while the second peak is due to the crystallization of the amorphous Zr/B alloy to form ZrB2. (C) 2013 AIP Publishing LLC.