Growth of B2 parent phase grain assisted by martensitic transformation in a nanocrystalline Ti-50.8Ni (at.%) shape memory alloy

2019 ◽  
Vol 159 ◽  
pp. 37-40 ◽  
Author(s):  
Xiao Liang ◽  
Fei Xiao ◽  
Hong Chen ◽  
Zhenxing Li ◽  
Xuejun Jin ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Parent Phase

Effect of L21 Ordering on the Martensitic and Intermartensitic Transformations in a Ni-Mn-Ga Shape Memory Alloy

2007 ◽  
Vol 130 ◽  
pp. 127-134
Author(s):  
Concepcio Seguí ◽  
Jaume Pons ◽  
Eduard Cesari
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Single Crystal ◽  
Shape Memory ◽  
Parent Phase ◽  
Heat Treatments ◽  
Free Energies ◽  
Transformation Temperatures ◽  
Reverse Martensitic Transformation ◽  
Order Degree

The present work analyses the influence of austenite ordering on a single crystal Ni-Mn- Ga alloy which displays, on cooling, a sequence of martensitic (MT) and intermartensitic (IMT) transformations. The MT and IMT show distinct behaviour after ageing in austenite: while the MT temperatures are not affected by the performed heat treatments, the IMT shifts toward lower temperatures after quenching from increasing temperatures, progressive recovery occurring upon ageing in parent phase. Such evolution can be related to changes in the L21 order degree, in the sense that ordering favours the occurrence of the intermartensitic transformation, while it does not affect noticeably the forward and reverse martensitic transformation temperatures. The closeness of the free energies of the different martensite structures allows to explain this behaviour.

Effects of Parent Phase Aging and Nb Element on the Microstructure, Martensitic Transformation, and Damping Behaviors of a Cu–Al–Mn Shape Memory Alloy

2020 ◽  
Vol 217 (6) ◽  
pp. 1900923
Author(s):  
Hanzu Li ◽  
Qingzhou Wang ◽  
Fuxing Yin ◽  
Chunxiang Cui ◽  
Gangling Hao ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Parent Phase

Factors for Controlling Martensitic Transformation Temperature of TiNi Shape Memory Alloy by Addition of Ternary Elements

2004 ◽  
Vol 842 ◽  
Author(s):  
Hideki Hosoda ◽  
Kenji Wakashima ◽  
Shuichi Miyazaki ◽  
Kanryu Inoue
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Stress Field ◽  
Shape Memory ◽  
Parent Phase ◽  
Site Occupancy ◽  
Atomic Volume ◽  
Clear Understanding ◽  
Scanning Calorimetry ◽  
Ternary Additions

ABSTRACTCorrelations between the changes in martensitic transformation start temperature (Ms) by addition of ternary elements X and several factors of the ternary additions were investigated for TiNi shape memory alloy. The change of Ms by addition of 1mol%X is referred to as ΔMs (in K/mol%), and ΔMs was systematically evaluated by differential scanning calorimetry experimentally using (Ti, X)50Ni50 solution-treated at 1273K for 3.6ks where the Ni content was kept constant to be 50mol%. The ternary additions X investigated are the transition metal (TM) elements selected from 4th period group (Zr, Hf) to 10th period group (Pd, Pt). The factors investigated are (1) the number of total outer d- and s-electrons (Nele), and electron hole number (NV), (2) electronegativity (EN), (3) atomic volume (VX) and (4) Mendeleev number (NM). It was found that the values of ΔMs are different even in a same period group; ΔMs of 6th period group are -133K/mol%Cr (3d-TM), -152K/mol%Mo (4d-TM) and -64K/mol%W (5d-TM) for example. The results found in the correlations between ΔMs and those factors are summarized as follows. (1) ΔMs depends on Nele and NV. However, the data are scattered because same Nele and NV are often given in a same period group. Then, other factors than Nele and NV are required for clear understanding of ΔMs. (2) ΔMs seems to become lowered slightly with increasing EN. (3) ΔMs weakly depends on atomic volume VX. Ternary addition with large VX increases ΔMs slightly, and with small VX decreases ΔMs largely. Since the stress field must be formed by substitution due to size mismatch, the type of stress field, tension/compression, may be an important role to determine the sign of ΔMs. (4) ΔMs shows a good correlation with NM as -9.4Kmol%−1/ΔNM where ΔNM is the difference in NM. This suggests that a ternary alloying element with smaller (larger) NM stabilizes the B19’ martensite (B2 parent) phase. Effect of site occupancy on Ms is also discussed only for Cr.

Micro and Macromechanical Study of Stress-Induced Martensitic Transformation in a Cu-Al-Be Polycrystalline Shape Memory Alloy

2006 ◽  
Vol 509 ◽  
pp. 87-92 ◽  
Author(s):  
F.M. Sánchez ◽  
G. Pulos
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Vector Fields ◽  
Displacement Vector ◽  
Optical Microscope ◽  
Image Sequences ◽  
Tension Test ◽  
Loading Device ◽  
Stress States

An experimental investigation of the micro and macromechanical stress-induced martensitic transformation in a Cu-Al-Be polycrystalline shape memory alloy is undertaken using a uniaxial tension test. Digital images are acquired at different stress states. The image sequences are analyzed to estimate the optical flow to get displacement vector fields. The experiments are carried out on a miniature hydraulic loading device mounted under an optical microscope. The stress-strain curves and associated images show stress-induced martensitic transformation in specific grains. Displacement vector fields for the polycrystalline shape memory alloy are obtained. They are inhomogeneous due to the martensitic transformation and inter-granular interactions.

scholarly journals Effect of Nd Addition on the Microstructure and Martensitic Transformation of Ni-Ti Shape Memory Alloys

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
M. Dovchinvanchig ◽  
C. W. Zhao ◽  
S. L. Zhao ◽  
X. K. Meng ◽  
Y. J. Jin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Earth Element ◽  
Transformation Behavior ◽  
Nd Addition ◽  
One Step ◽  
Niti Matrix ◽  
Start Temperature

The effect of rare earth element Nd addition on the microstructure and martensitic transformation behavior of Ni50Ti50−xNdx(x=0, 1, 3, 7, 20) shape memory alloy was investigated experimentally. The results showed that the microstructure of Ni-Ti-Nd ternary alloy consists of the NiNd phase and the NiTi matrix. One-step martensitic transformation was observed in all alloys. The martensitic transformation start temperatureMsincreased gradually with increasing Nd content for Ni-Ti-Nd alloys.

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.

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