Fig. 5: In situ TEM showing the crystallization mechanism and the final microstructure formed in a confined environment at a subcritical heating rate of about 220 K s−1 in a vacuum.
a Heating profile of a glassy Cu47.5Zr47.5Al5.0 thin foil. Two crystallization temperatures Tx1 and Tx2 corresponding respectively to the onset of Cu10Zr7 and B2 phase formation—represented on the right-hand by SAED patterns—can be identified. The value of the glass-transition temperature, Tg, of a ribbon sample is taken from Cheng et al.28 and was obtained by ultra-fast scanning calorimetry. The maximum temperature reached on heating was Tmax ≈ 944 K, followed by cooling at a rate of ~1090 K s−1. The phase transformation was confined to a volume of ~16 × 0.05 μm3 (area × thickness). b Bright-field STEM micrograph and SAED (inset in the top-right corner) of the final microstructure. The white rectangle highlights a B2 grain surrounded mostly by Cu10Zr7, and it also marks the area of the corresponding fast-Fourier-transform pattern shown as the inset in the bottom-right corner. c HAADF image and the corresponding EDX of the individual elements (Cu: green; Zr: red; and Al: blue) of the area in the B2 crystal vicinity from part b.
