Thermoelastic transition kinetics of a gamma irradiated CuZnAl shape memory alloy

Ni24.7Ti50.3Pd25.0 high temperature shape memory alloy with narrow thermal hysteresis and high thermal stability

“…Figure 2b shows the plot of ln(/A p 2 ) vs. 1/A p drawn using the data provided in Table 2. The calculated E a , 1931 kJ/mol, for the present alloy is significantly higher than that for Cu-Zn-Al (350-450 kJ/mol) and Ni-Ti (210-531 kJ/mol) shape memory alloys [22][23][24].…”

Effect of Hydrostatic Pressure on Thermodynamic Properties of NiTi Shape Memory Alloy

“…This structural displacement is a result of thermoelastic martensitic transformation. Thermoelastic martensitic transformations develop by three mechanisms: nucleation, growth, and impingement of growing new phase particles [19,23]. Furthermore, the Gibbs free ener-gies for austenite phase and martensite phase transformation can be expressed by the following relation [24,25],…”

“…Therefore, it can be used to analyze the nucleation and growth mechanisms in TMTs. Kissinger supported that the change in peak temperature with variation of the heating/cooling rate could be used to calculate the activation energy [19,31]. According to that approach, the activation energy for phase transformation is given by the following relation,…”

“…Thus, the plot of ) ln( 2 p A versus 1/A p gives the slope -R E a from which the activation energy is calculated. Furthermore, the Ozawa method was calculated to determine the activation energy [7,19]. The fitting curves that are used in the calculation of activation energies for both methods are shown in Fig.…”

“…Heating rate is another concern in testing SMAs. There are some publications on the thermal and mechanical effects on the transformation behavior of NiTi SMA [19][20].…”