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The deformation behavior of as-quenched 2024 Al–Cu–Mg alloy has been experimentally studied. The experiments are designed to cool specimens to the desired temperature with a constant cooling rate, i.e., 5 K/s. Isothermal tensile tests are performed over a range of 573–723 K temperature and (0.01, 0.1, and 1 s−1) strain rates to find out the flow stresses and microstructures after deformation. Due to the nonuniform deformation mechanisms (solid solution versus solid solution and precipitation), two types of Arrhenius model are established for the temperature range of 573–673 K and 673–723 K, respectively. For temperature between 573 and 673 K, the activation energy is dependent on temperature and strain rate, and the value of activation energy decreases with the increases of temperature and strain rate. Compared with the ideal variation trend with no consideration of precipitation, the largest difference of activation energy is found at the temperature of 623 K which is the nose temperature of 2024 alloy.

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An experiment was performed to investigate the influence of four dissolved salts (NaCl, CaCl 2 , Na 2 SO 4 and MgSO 4 ) on heat transfer. Concentration of all salts varied from 0.01 M to 0.4 M. And deionized water (DI water) was used as the solvent. The aluminum alloy 2024 thin sheets were heated to 495℃ and quenched by two spray nozzles with a constant range of volumetric flux. Time-temperature curves were smoothed by B-spline approximation with a smoothing parameter of 10 -4 . The results indicate that only MgSO 4 solution increases both nucleate boiling and transition boiling heat flux. Solution of CaCl 2 has the greatest influence on nucleate boiling heat transfer, followed by Na 2 SO 4 compared with the minimum influence of NaCl. These effects are attributed to the surface tension gradient, transition concentration and vapor pressure for different salts. The largest heat flux enhancement is observed at concentration of 0.2 M for solutions of NaCl, CaCl 2 and MgSO 4 in contrast to 0.06 M for Na 2 SO 4 .