Showing 3 results for Dsc
A. Karimi Taheri, Kazeminezhad, A. Kiet Tieu,
Volume 4, Issue 1 (6-2007)
Abstract
Abstract: The theoretical calculation of dislocation density in different regions of a deformed
workpiece of 99.99% pure copper has been carried out using different procedures consisting of
Finite Element Method (FEM) and hardness measurement. To assess the validity of the results
pertaining to these procedures, the dislocation density is experimentally measured utilizing the
Differential Scanning Calorimetry (DSC). Comparing the predicted and experimental results, it
was found that the average error in prediction of the dislocation density by the hardness
measurement and FEM is 12% and 2.5%, respectively. Also, for further confirmation of the
evaluated dislocation density of each region of the deformed workpiece, the annealing process was
carried out and in the region of higher dislocation density, a finer grain size was observed.
H. Shahmir, M. Nili Ahmadabadi, F. Naghdi,
Volume 5, Issue 4 (12-2008)
Abstract
Abstract: In the present study the effect of thermomechanical treatment (cold work and annealing) on the
transformation behavior of NiTi shape memory alloys was studied. Differential scanning calorimetry was used to
determine transformation temperature and its relation to precipitates and defects. Three alloys including Ti-50.3at.%
Ni, Ti-50.5at.% Ni (reclamated orthodontic wires) and 50.6at.% Ni alloy were annealed at 673 K and 773 K for 30
and 60 min after 15% cold rolling. It was found that the transformation characteristics of these alloys are sensitive to
annealing treatment and composition. The temperature range of transformation is broadened during cold working and
after subsequent annealing, the intermediate phase was appeared. The peaks become sharper and close together on
each cooling and heating cycle with increasing annealing temperature and time
A. Shokuhfar, S. Ahmadi, H. Arabi, S. Nouri,
Volume 6, Issue 3 (9-2009)
Abstract
Abstract: Guinier-Preston (GP) zone formation and precipitation behavior of T1 (Al2CuLi) phase during the ageingof an Al-Cu-Li-Zr alloy was studied by differential scanning calorimetry (DSC) technique and electrical resistancemeasurement of the samples. Results show that endothermic effects in the thermograms of the alloy between 180°Cand 240°C can be related to the enthalpy of GPzones dissolution. Formation of GPzones in the structure increasedhardness, tensile strength and electrical resistance of the Al-Cu-Li-Zr alloy. Furthermore, precipitation of T1 phaseoccurred in temperature range of 250ºC to 300ºC whereas its dissolution occurred within the temperature of 450-530ºC. Activation energies for precipitation and dissolution of T1 phase which were determined for the first time inthis research, were 122.1(kJ/mol) and 130.3(kJ/mol) respectively. Results of electrical resistance measurementsshowed that an increase in the aging time resulted in the reduction of electrical resistance of the aged samples.
