Cooling Rate Calculation of Non-Equilibrium Aluminum Alloy Powders Prepared by Gas Atomization
Journal article, 2009
The cooling rate of aluminum alloy powders prepared by ultrasonic gas atomization process was calculated through the convection heat transfer principle. A simple and theoretical model is established, which can be expressed as vertical bar dT(d)/dt vertical bar =12/rho.C(p) . (T(d) - T(f)) . k(g)/d(2). The average cooling rates of Al-Ni-Ce-Fe-Cu alloy powders prepared by argon gas atomization and by helium gas atomization are about 10(4)similar to 10(7) K/s and 10(5)similar to 10(8) K/s, respectively. The critical cooling rate is calculated to be 3.74 x 10(5) K/s for Al-Ni-Ce-Fe-Cu alloy amorphous powders prepared by argon gas atomization. The cooling rates of gas-atomized powder particles estimated from secondary dendrite arm spacing are in consistence to those predicted from the theoretical model.