Amorphous cooling rate

Using rapid solidification technology molten metal is quench cast at a cooling rate up to 10 °C/s as a continuous ribbon. This ribbon is subsequently pulverized to an amorphous powder. RST powders include aluminum alloys, nickel-based superalloys, and nanoscale powders. RST conditions can also exist in powder atomization. 

Using the fluxing technique, Lau and Kui [33] determined that the critical cooling rate for forming a 7-mm diameter bulk amorphous Pd4QNi4()P2o cylinder was 0.75 K/sec. From this value, they estimated that the steady-state nucleation frequency was on the order of lO" m s. On the other hand, Drehman and Greer [34] estimated that the steady state nucleation frequency at 590 K is 10 m" s, which is also the maximum... 

Fig. 7 Relative integrated intensities under the peaks (left scale) and relative degree of crystallinity (right scale) obtained from wide-angle X-ray scattering data for D7732C2310 quenched from T = 115 to 30°C. The cooling rate was 30°Cmin 1. The arrow indicates the nominal point at which the final temperature was reached. For convenience, the amorphous peak intensity has been divided by 5. (Reprinted with permission from [ 107]. Copyright 2003 American Chemical Society)...

Molecular-Weight and Cooling-Rate Dependence of Simulated Tg for Amorphous Polystyrene. 

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