A series of alternative quenching experiments at 7.7 GPa and ~2000 K were carried out using the hightemperature cell of an opposite-anvil toroid-type high-pressure apparatus. In this case, the compression geometry allows performing uniaxial compression with quite significant deviatoric. The cell was pressure-calibrated at room temperature using phase transitions in Bi, PbSe and PbTe, and temperature-calibrated under pressure using well-established reference points: melting of Si, NaCl, CsCl, Pt, Rh, Al 2 O 3 , Mo and Ni-Mn-C ternary eutectic. The details are described elsewhere. Samples were gradually compressed to 7.7 GPa, heated to the desired temperature for 5 minutes, then quenched by turning off the power and slowly decompressed. The typical time to apply and release pressure was about 10 minutes. Pressure and temperature uncertainties were estimated to be about 0.5 GPa and 30 K, respectively.