Dynamic medium-range order (MRO) fluctuations in supercooled glass-forming alloys

The theory assumes that the macroscopic behavior of metallic glasses is determined by the cooperative fluctuations in the supercooled melt. We have found that the temperature dependence of the averaged correlation length shows an almost material-independent variation in the case of low molecular organic compounds, polymers, chalcogenide glass-formers and two metallic glass-formers. Here we want to monitor in-situ the fluctuations of the MRO via pair distribution functions (PDFs). We choose two glass-forming alloys based on Pt and Pd with different macroscopic vitrification and crystallization kinetics. The vitrification and devitrification at cooling/heating rates up to 10,000 K/s, as well as quasi isothermal modulated DSC at frequencies as high as 1 kHz, can be studied upon a MEMS-chip based fast calorimetry, i.e. by using the state-of-the-art Flash DSC 2+ device. In-situ XRD with proper spatial and temporal resolution will be collected using a fast DECTRIS detector.