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Perspective in Development of Shape Memory Materials Associated with Martensitic Transformation
Zuyao XU,

材料科学技术学报 , 1994,
Abstract: By consideration of the characteristics of martensitic transformation and the derivation from the application of the group theory to martensitic transformation, it may be concluded that the shape memory effect (SME) can be attained in materials through a martensitic transformation and its reverse transformation. only when there forms single or nearly single variant of martensite, with an absence of the factors causing the generation of the resistance against SME. on this principle, various shape memory materials including nonferrous alloys. iron-based alloys and ceramics containjng zirconia are expected to be further developed. A criterion for thermoelastic martensitic transformation is presented, Factors which may act as the resistance against SME in various materials are briefly described
Martensitic Transformation of TiNi Shape Memory Alloy Fiber Reinforced Ni Matrix Composites
Lishan CUI,Yan LI,Yanjun ZHENG,Huibin XU,

材料科学技术学报 , 2003,
Abstract: In this paper, a TiNi shape memory alloy fiber Ni matrix composite was fabricated by an electroplating method using TiNi alloy as the cathode and Ni as the anode. The constrained martensitic transformation behaviors of the TiNi alloy were studied by differential scanning calorimeter (DSC), and the results showed that two endothermic peaks appear on the DSC heating curves and the reverse transformation temperatures increase with increasing prestrain levels. Moreover, comparing to the free transformation, the temperature window of the constrained reverse transformation is widely expanded due to the influence of recovery stress.
Observation of the two way shape memory effect in an atomistic model of martensitic transformation  [PDF]
E. A. Jagla
Physics , 2015,
Abstract: We study a system of classical particles in two dimensions interacting through an isotropic pair potential that displays a martensitic phase transition between a triangular and a rhomboidal structure upon the change of a single parameter. Previously it was shown that this potential is able to reproduce the shape memory effect and super-elasticity, among other well known features of the phenomenology of martensites. Here we extend those previous studies and describe the development of the more subtle two-way shape memory effect. We show that in a poly-crystalline sample, the effect can be associated to the existence of retained martensite within the austenite phase. We also study the case of a single crystal sample where the effect is associated to particular orientations of the dislocations, either induced by training or by an ad hoc construction of a starting sample.
Ferromagnetic interactions and martensitic transformation in Fe doped Ni-Mn-In shape memory alloys  [PDF]
D. N. Lobo,K. R. Priolkar,S. Emura,A. K. Nigam
Physics , 2014, DOI: 10.1063/1.4901469
Abstract: The structure, magnetic and martensitic properties of Fe doped Ni-Mn-In magnetic shape memory alloys have been studied by differential scanning calorimetry, magnetization, resistivity, X-ray diffraction (XRD) and EXAFS. While Ni$_{2}$MnIn$_{1-x}$Fe$_{x}$ ($0 \le x \le 0.6$) alloys are ferromagnetic and non martensitic, the martensitic transformation temperature in Ni$_{2}$Mn$_{1.5} $In$_{1-y}$Fe$_{y}$ and Ni$_{2}$Mn$ _{1.6} $In$_{1-y}$Fe$_{y}$ increases for lower Fe concentrations ($y \le 0.05$) before decreasing sharply for higher Fe concentrations. XRD analysis reveals presence of cubic and tetragonal structural phases in Ni$_{2}$MnIn$_{1-x}$Fe$_{x}$ at room temperature with tetragonal phase content increasing with Fe doping. Even though the local structure around Mn and Ni in these Fe doped alloys is similar to martensitic Mn rich Ni-Mn-In alloys, presence of ferromagnetic interactions and structural disorder induced by Fe affect Mn-Ni-Mn antiferromagnetic interactions resulting in suppression of martensitic transformation in these Fe doped alloys.

GENG Guili,BAI Yujun,PENG Qifeng
金属学报(英文版) , 1996,
Abstract: The kinetics of the reversible martensitic transformation in a Cu-Zn-Al-Mn-Ni shape memory alloy has been studied by means of differential scanning calorimetry.The apparent activation energy has been calculated and the kinetic equations of positive and adverse martensitic transformation have been established with the variations of temperature and time.
Effects of Predeformation on the Reverse Martensitic Transformation of TiNi Shape Memory Alloy
Yanjun ZHENG,Lishan CUI,Fan Zhang,Dazhi YANG,

材料科学技术学报 , 2000,
Abstract: DSC was used to study the effects of predeformation on the reverse martensitic transformation of near-equiatomic TiNi alloy. Both the start temperature A(s) and the finish temperature A(f) of the reverse transformation increased with increasing degree of predeformation, but the algebraic difference between A(s) and A(f) decreased with increasing predeformation until it reached a minimum value, then remained unchanged with further deformation. Transformation heat also increased with increasing predeformation until it reached a maximum value, then decreased with further predeformation. All the phenomena above were considered to be closely related with the release of elastic strain energy during predeformation.
Martensitic Transformation and Magnetic-Field-Induced Strain in Magnetic Shape Memory Alloy NiMnGa Melt-Spun Ribbon
Shihai GUO,Yanghuan ZHANG,Jianliang LI,Baiyun QUAN,Yan QI,Xinlin WANG,
Shihai GUO
,Yanghuan ZHANG,Jianliang LI,Baiyun QUAN,Yan QI and Xinlin WANG

材料科学技术学报 , 2005,
Abstract: A magnetic shape memory alloy with nonstoichiometric Ni5oMn27Ga23 was prepared by using melt-spinning technology. The martensitic transformation and the magnetic-field-induced strain (MFIS) of the polycrystalline melt-spun ribbon were investigated. The experimental results showed that the melt-spun ribbons underwent thermal-elastic martensitic transformation and reverse transformation in cooling and heating process and exhibited typical thermoelastic shape memory effect. However the start temperature for martensitic transformation decreased from 286 K for as-cast alloy to 254 K for as-quenched ribbon and Curie temperature remains approximately constant. A particular internal stress induced by melt-spinning resulted in the formation of a texture structure in the ribbons, which made the ribbons obtain larger martensitic transformation strain and MFIS. The internal stress was released substantially after annealing, which resulted in a decrease of MFIS of the ribbons.
A Model for Conjoint Shape Memory and Pseudo-Elastic Effects during Martensitic Transformation  [PDF]
K. Boubaker
ISRN Metallurgy , 2012, DOI: 10.5402/2012/612891
Abstract: Shape memory alloys (SMA) are metals which can restore their initial shape after having been subjected to a deformation. They exhibit in general both nonlinear shape memory and pseudoelastic effects. In this paper, shape memory alloy (SMA) and its constitutive model with an empirical kinetics equation are investigated. A new formulation to the martensite fraction-dependent Young modulus has been adopted and the plastic deformation was taken into account. To simulate the variations, a one-dimensional constitutive model was constructed based on the uniaxial tension features. 1. Introduction Recently, smart metals and alloys have been extensively used in several metallurgical applications, due to their great potential in updated structures and design [1–10]. Among these materials, shape memory alloys (SMA) have attracted more attention, due to their ability to develop extremely large recoverable strains and great forces in the field of biomedical, metallurgy, aerospace, and civil structures [5–10]. In SMA matrices, pseudoplastic effect creates different stress strain behavior resulting in a stress strain curve which lies on the curve produced by the initial linear elastic response during loading. Consecutive and continued unloading may produce linear elastic behavior that eventually returns the structure to the zero stress strain state. In the present work, an attempt is made to model typical martensitic transformations occurring in shape memory alloys, taking into account pseudoplasticity patterns. In this martensitic transformation, austenite undergoes transformation to form different variants of martensite under a controlled mechanical loading. The formation of martensite in the material is monitored through the coexistence of the initial austenite phases and martensite inside periodic units. Solutions for the implemented governing equations are obtained numerically via explicit numerical protocols and compared to some records presented in the recent related literature [11–18]. 2. Model Patterns 2.1. Governing Equations The studied system is a mono-dimensional rod subjected to axial solicitation (Figure 1). The phase transformations in this considered structure occur by nucleation and growth of platelet inclusions perpendicular to -axis (Figure 1). In this configuration, elastic modulus local expression can be obtained considering the medium as a succession of austenite-martensite periodic units (Figure 1). Figure 1: The studied model. The main assumptions of the present model consists of setting one scalar internal variable which represents the
Characterization of Magnetic Transition and Martensitic Transformation and Shape Memory Effect in Ni46Mn35Ga19 Single Crystal
WU Liang,ZHANG Jian,MA Yong,KONG Chun-yang
Journal of Chongqing Normal University , 2009,
Abstract: As a new class of shape memory materials, the NiMnGa alloy was one of the earliest discovered Magnetic Shape Memory Alloy. Many scholars investigated its characterizations and applications carried out in-depth since the discovery, but actually to lack of system’s attribute to the co-occurrence of magnetic and martensitic transformations. In this paper, the co-occurrence of magnetic and martensitic transformations in Ni46Mn35Ga19 single crystal grown by the Czochralski method were characterized by various ways, such as heat flow, resistance, alternating-current magnetic susceptibility, and strain measurements. In addition, the experimental results are analyzed and discussed according to the characteristics of shape memory and the mechanism of preferential orientation of the martensitic variants.Accompanying with this transformation behavior, a large spontaneous transition strain of -0.89% in zero field and a large magnetic-field-enhanced strain of -1.90% is observed. This value of -1.90% is approximately two times larger than that detected in zero field cooling.
Ab initio study of the martensitic transformation of NiTi shape memory alloys

Gong Chang-Wei,Wang Yi-Nong,Yang Da-Zhi,

物理学报 , 2006,
Abstract: In order to systematically understand the mechanism of martensitic transformation of NiTi shape-memory alloy, and to study the effect of temperature and stress on the electronic structure, we have carried out first-principles calculations based on the density-functional theory (DFT). Analysis of density of states shows that martensitic transformation induces the Fermi face to shift and the density of states near the Fermi face to decrease. With the temperature decreasing and deformation increasing,the density of state of B2 phase and the degree of energy band overlaps increase,thus the stability decrease.
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