Papers by Keyword: Differential Scanning Calorimeter

Abstract: Dissimilar aluminum butt joints were successfully joined using a friction stir welding machine, employing four welding speeds (50, 60, 70, 80 mm/min), four rotational speeds (900, 1000, 1100, 1200 rpm), and four different weld tool profiles (T1=12/4, T2=15/5, T3=16/4, T4=20/5 in D/d ratio). The corrosion analysis suggests that specimens 9, 10, 11, and 13 exhibit higher corrosion resistance, with a breaking potential of -0.6 eV, while specimen 8 shows the lowest corrosion resistance with a breaking potential of -2.1 eV. The results from the differential scanning calorimeter illustrate the formation of precipitation dissolution due to high heat generation at the nugget zone. An eddy current defect detector experiment was conducted to detect surface flaws in the welded samples. Few surface cracks were observed in the T2 profile specimens, which have a larger contact region or shoulder diameter, while more surface cracks were observed in the T1 profile samples.

Abstract: Using the flux processing technique, the undercooling of pure silver melts could reach to 205K. Combining the Differential Scanning Calorimeter (DSC) technique, the specific heat of pure silver melts was measured, which showed a linear dependence on temperature in the range of the obtained undercooling from 0 K to 205K. The related thermodynamic properties of silver, such as the entropy change, the enthalpy change and the Gibbs free energy difference between the undercooled melt and the solid phase, were derived from the measured specific heat. The results showed that the model of Singh-Holz can reveal the reality of the non-equilibrium solidification more accurately than other models.