New trends in differential scanning calorimetry

1989 ◽  
Vol 67 (6) ◽  
pp. 983-990 ◽  
Author(s):  
H. Tachoire ◽  
V. Torra

Recent applications of differential scanning calorimetry in the study of solid–solid transformations are presented. The importance of the deconvolution of the thermograms and of the modelling of the calorimetric equipment is stressed.Investigations of the phase transformations of the martensitic type in shape-memory alloys have made clear the influence of thermomechanical treatment of the material and have evaluated the influence of defects on the dynamics of transformation. A combination of calorimetric and acoustical observations has demonstrated irreversibilities, even in the so-called thermoelastic transitions. Keywords: martensitic transformation, differential scanning calorimetry, entropy production, thermomechanical treatments, acoustic emission.

2008 ◽  
Vol 59 ◽  
pp. 92-100
Author(s):  
Ana Cris R. Veloso ◽  
Rodinei Medeiros Gomes ◽  
Dagoberto Brandao Santos ◽  
I.C.E.G. Lima ◽  
Severino Jackson Guedes de Lima ◽  
...  

In this study Cu-13.8Al alloys with 3.0% and 4.0% (wt%) of nickel were obtained by induction melting. The effect of homogenization heat treatment and hot rolling on the transformation temperatures of these alloys was investigated by differential scanning calorimetry. It was observed that the transformation temperatures increase with long homogenization times, and also by hot rolling, and this displacement is smaller for alloys with 4.0% of nickel. In both alloys in the quenched state, the reversion reaction is characterized by the appearance of multiple peaks attributed to the presence of martensites 2H and 18R. The influence of the rolling process must be associated with the loss of Ni and Al during the process.


2008 ◽  
Vol 584-586 ◽  
pp. 127-132 ◽  
Author(s):  
Anastasia E. Sergeeva ◽  
Daria Setman ◽  
Michael Zehetbauer ◽  
Sergey Prokoshkin ◽  
Vladimir V. Stolyarov

The aim of this paper is the investigation of electroplastic deformation (EPD) and subsequent annealing influence on martensitic transformation in the shape memory Ni50.7Ti49.3 alloy. Using differential scanning calorimetry method it was shown that EPD at the low strain stimulates structure relaxation and recovers martensitic transformation in cooling, which is usually suppressed by cold rolling.


Proceedings ◽  
2020 ◽  
Vol 38 (1) ◽  
pp. 15
Author(s):  
Andrade ◽  
Soares ◽  
Nobrega ◽  
Hilário ◽  
Santos

This paper presents a characterization processes study of metallic alloys, more specifically the shape memory alloys (SMA) composed by Nickel and Titanium (NiTinol). Two different wire suppliers were studied, starting with metallographic analysis until observe the contours of the grain wires. Differential scanning calorimetry (DSC) test was also performed to obtain phase transformation temperatures of the NiTinol alloys. Finally, after several tensile tests, some results were obtained for stresses, strains, elasticity modules and maximum rupture deformation.


2005 ◽  
Vol 475-479 ◽  
pp. 1973-1976 ◽  
Author(s):  
Ailian Liu ◽  
Xianglong Meng ◽  
Wei Cai ◽  
Lian Cheng Zhao

The effect of cerium addition on the martensitic transformation behavior and microstructure of Ti50-x/2Ni50-x/2Cex (x=0, 0.5, 2, 5 and 10at.%) alloys have been studied by differential scanning calorimetry (DSC) and energy dispersive spectroscopy (EDS). The results show that the addition of cerium affects the martensitic transformation temperature obviously. With the increase of Ce content, the phase transformation temperatures first increase rapidly and then decrease slightly, which may be attributed to the change of the Ni/Ti ratio in matrix. Moreover, the dispersed Ce-riched second particles with various morphologies are observed in TiNiCe alloys.


2013 ◽  
Vol 203-204 ◽  
pp. 125-128 ◽  
Author(s):  
Zdzisław Lekston ◽  
Maciej Zubko

The NiTi shape memory alloys with ternary additions of Co are being considered for future applications in the construction of medical products. In this study the commercially available Ni50.8Ti49.2 medical alloy and Ti50Ni48.7Co1.3 alloy obtained by the conventional VIM technique, were used to prepare shape memory and superelastic staples. The phase transformations in the wires of those alloys after various thermo-mechanical and thermal treatments have been defined by the differential scanning calorimetry (DSC) method and three-point bending and free recovery ASTM F2082-06 tests. In this work the courses of phase transformations in the studied alloys were investigated by means of the low-temperature X-ray powder diffraction method. In both alloys after cold working and annealing during cooling two phase transformations occur: from parent B2-phase to rhombohedral R-phase and monoclinic B19’ martensite phase. Such phase transformations are fully reversible during heating and the obtained characteristic temperatures from DSC and X-ray powder diffraction measurements are in good agreement.


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