Effect of Electroplastic Deformation on Martensitic Transformation in Coarse Grained and Ultrafine Grained Ni-Ti Shape Memory Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 127-132 ◽  
Author(s):  
Anastasia E. Sergeeva ◽  
Daria Setman ◽  
Michael Zehetbauer ◽  
Sergey Prokoshkin ◽  
Vladimir V. Stolyarov
Keyword(s):  
Differential Scanning Calorimetry ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Coarse Grained ◽  
Scanning Calorimetry ◽  
Structure Relaxation ◽  
Differential Scanning Calorimetry Method ◽  
Ultrafine Grained

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.

scholarly journals Nanocrystal, phase transformation and microstructure of Ni50Ti50 shape memory alloy

2018 ◽  
Vol 24 (02) ◽  
pp. 22-25
Author(s):  
Dovchinvanchig M ◽  
Chunwang Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
One Step ◽  
Niti Matrix ◽  
Electronic Microscope

The nanocrystal, phase transformation and microstructure behavior of Ni50Ti50 shape memory alloy was investigated by scanning electronic microscope, X-ray diffraction and differential scanning calorimetry. The results showed that the microstructure of Ni-Ti binary alloy consists of the NiTi2 phase and the NiTi matrix phase. One-step phase transformation was observed alloy.

Nanostructured Shape Memory TiNi Alloy Processed by Severe Electroplastic Deformation

2008 ◽  
Vol 584-586 ◽  
pp. 507-512 ◽  
Author(s):  
Vladimir V. Stolyarov
Keyword(s):  
Cold Rolling ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Fracture Strain ◽  
Coarse Grained ◽  
Tini Alloy ◽  
Current Effect ◽  
Electroplastic Rolling ◽  
Ultrafine Grained ◽  
A Current

Electropulse current effect during cold rolling on deformability, nanostructure formation and mechanical behavior in coarse-grained (CG) and ultrafine-grained (UFG) TiNi alloys enriched by nickel is investigated. The UFG sample subjected to cold rolling with current has a fracture strain (е = 1.91) which is higher than that without a current (е = 0.59). As a result of cold rolling with a current and a subsequent annealing at 400-450 °C, nanostructure is formed in both alloys, which leads to a significant enhancement of yield and ultimate stresses. It has been shown that the efficiency of electroplastic rolling depends on the purity of the alloys.

scholarly journals Microstructural characterization of Cu82.3Al8.3Mn9.4 shape memory alloy after rolling

10.30544/314 ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 281-289
Author(s):  
Mirko Gojić ◽  
Stjepan Kožuh ◽  
Ivana Ivanić ◽  
Magdalena Selanec ◽  
Tamara Holjevac Grgurić ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Microstructural Characterization ◽  
Rolling Process ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Hot And Cold Rolling

In this paper, the microstructure of Cu82.3Al8.3Mn9.4 (in wt. %) shape memory alloy after hot and cold rolling was investigated. The Cu82.3Al8.3Mn9.4 alloy was produced by a vertical continuous casting method in the form a cylinder rod of 8 mm in diameter. After the casting, hot and cold rolling was performed. By hot rolling a strip with a thickness of 1.75 mm was obtained, while by cold rolling a strip with a thickness of 1.02 mm was produced. After the rolling process, heat treatment was performed. Heat treatment was carried out by solution annealing at 900 °C held for 30 minutes and water quenched immediately after heating. The microstructure characterization of the investigated alloy was carried out by optical microscopy (OM), scanning electron microscopy (SEM) equipped with a device for energy dispersive spectroscopy (EDS). Phase transformation temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC) method. The homogenous martensite microstructure was confirmed by OM and SEM micrographs after casting. During rolling the two-phase microstructure occurred. Results of DSC analysis showed martensite start (Ms), martensite finish (Mf), austenite start (As) and austenite finish (Af) temperatures.

Thermal Cycling Influence on the Transformation Characteristics of a Ni50Ti48Nb2 Shape Memory Alloy

2017 ◽  
Vol 68 (5) ◽  
pp. 991-996
Author(s):  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Gabriela Liliana Jicmon ◽  
Ruxandra Elena Dumitrescu ◽  
Mihai Branzei
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shape Memory Alloy ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Critical Points ◽  
Mechanical Stability ◽  
Alloy Sample ◽  
Scanning Calorimetry ◽  
Metallic Part ◽  
Two Samples

The alloy was chosen in order to obtain a shape memory alloy having a wider hysteresis than equiatomic NiTi, that involves a better thermo-mechanical stability. Two samples investigated by differential scanning calorimetry (DSC) were previously annealed at 800oC/12 h and, respectively, 900 �C/12 h followed by furnace cooling. These were afterwards submitted to thermal cycling. The thermal cycling of a Ni50Ti48Nb2 alloy sample previously annealed at 900 �C/12 h results in lower critical points and higher hysteresis values as compared to those of the sample annealed at 800�C/12h, also submitted to thermal cycling. Thus, annealing a metallic part made of such an alloy at 900� C/12 h followed by thermal cycling prior to putting it into service enhances its reliability.

Effect of Ce Addition on Martensitic Transformation Behavior of TiNi Shape Memory Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 1973-1976 ◽  
Author(s):  
Ailian Liu ◽  
Xianglong Meng ◽  
Wei Cai ◽  
Lian Cheng Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Energy Dispersive Spectroscopy ◽  
Transformation Temperature ◽  
Martensitic Transformation Temperature ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
Ce Content

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.

New trends in differential scanning calorimetry

1989 ◽  
Vol 67 (6) ◽  
pp. 983-990 ◽  
Author(s):  
H. Tachoire ◽  
V. Torra
Keyword(s):  
Differential Scanning Calorimetry ◽  
Acoustic Emission ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phase Transformations ◽  
Entropy Production ◽  
Thermomechanical Treatment ◽  
Scanning Calorimetry

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.

scholarly journals Microstructural and Mechanical Stability of a Ti-50.8 at.% Ni Shape Memory Alloy Achieved by Thermal Cycling with a Large Number of Cycles

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 227 ◽  
Author(s):  
Churakova ◽  
Gunderov
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Temperature Change ◽  
Mechanical Stability ◽  
Martensitic Transformations ◽  
Coarse Grained ◽  
Ultrafine Grained ◽  
Number Of Cycles

The influence of thermal cycling (TC) with a large number of cycles on the microstructure, the parameters of martensitic transformations (MTs), and the mechanical properties of a Ti-50.8 at.% Ni shape-memory alloy in coarse-grained (CG) and ultrafine-grained (UFG) states was investigated. The effect of microstructural and mechanical stability was found in both coarse-grained and ultrafine-grained states starting from the 100th cycle of martensitic transformations. In addition, an unusual temperature change was observed in martensitic transformations occurring with the formation of an intermediate R phase.

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