Osman Adiguzel

Fırat University · Department of Physics

Metals and alloys have different phases at different conditions in crystallographic basis, and these phases are described in phase diagrams as alloy composition-temperature, or composition-pressure dependent. Beta phases of alloys mainly have bcc-based ordered or disordered structure and these phases are very sensitive to external conditions, and p...

Shape memory alloys have a peculiar property to return to a previously defined shape on heating after deformation in low temperature product phase region. These alloys take place in a class of functional materials due to the response to the variation of temperature, and they are used shape memory elements in a wide range of industry; in particular,...

Shape memory effect is a peculiar property exhibited a certain alloy systems with special chemical compositions in the β-phase fields of alloys and other materials like polymers. Successive martensitic transformations, thermal induced and stress induced martensitic transformations, govern shape memory effect in shape memory alloys. Martensitic tran...

Shape memory effect is a peculiar property exhibited by a series of alloy systems. This property is characterized by the recoverability of desired shape of the material at different conditions, and these alloys take place in a class of smart materials due to this property. Shape memory effect is based on martensitic transformation, which is a solid...

Shape memory alloys have a peculiar property to return to a previously defined shape or dimension when they are subjected to variation of temperature. Shape memory effect is facilitated by martensitic transformation governed by changes in the crystalline structure of the material. Martensitic transformations are first order lattice-distorting phase...

Shape memory effect is a peculiar property exhibited by certain alloy systems, and shape memory alloys are recognized to be smart materials. These alloys have important ability to recover the original shape of material after deformation, and they are used as shape memory elements in devices due to this property. The shape memory effect is facilitat...

Shape memory alloys take place in a class of smart materials by exhibiting a peculiar property called shape memory effect. This property is characterized by the recoverability of desired shape on the material at different conditions. Shape memory effect is based on a solid state phase transition, martensitic transformation, which occurs in the mate...

Shape memory alloys transform martensitically to close packed structures and have internally faulted structures in martensitic condition, and they are very sensitive to cycling and ageing effects. In noble metal copper based alloys, martensitic transformation occurs from a cubic structure with B2 (or DO3) order to a long period layered structure 9R...

Shape memory alloys exhibit a peculiar property called shape memory effect based on a first order solid state phase transformation, martensitic transformation which occurs in thermal manner on cooling the materials. Martensitic transformation is evaluated by the structural changes in microscopic scale. Copper-based ternary alloys exhibit shape memo...

Shape memory effect is a peculiar property exhibited by certain alloy system. This behavior is facilitated by martensitic transformation, and shape memory properties are intimately related to the microstructures of alloys; in particular, the morphology and orientation relationship between the various martensite variants. Martensitic transformation...

Shape memory alloys exhibit a peculiar property, shape memory effect that is the result from the structural changes in microscopic scale. These alloys return to previously defined shapes when they are subjected to variation of temperature after deformation of the low temperature phase. Shape-memory effect is based on martensitic transformation, wit...

Shape memory alloys have a peculiar property to return to a previously defined shape or dimension when they are subjected to variation of temperature. These alloys have the important ability to ‘remember’ their shape and recover this shape after deformation, and they are used as shape memory elements in devices due to this property. The behavior of...

Martensitic transformations are first order solid state phase transitions and occur in the materials on cooling from high temperature. Shape memory effect is an unusual property exhibited by certain alloy systems, and based on martensitic transformation. The shape memory property is characterized by the recoverability of previously defined shape or...

Shape memory effect is an unusual property exhibited by certain alloy systems, and based on a displacive transition, martensitic transition. Copper based alloys exhibit this property in metastable b-phase region and bcc-based high temperature parent phase structures martensitically turn into the layered complex structures on cooling from high tempe...

Martensitic transformations are first order displacive transitions and occur in the materials on cooling from high temperature. Shape memory effect is an unusual property exhibited by certain alloy systems, and leads to martensitic transition. Copper-based alloys exhibit this property in beta phase field which possess simple bcc- structures, austen...

Shape memory alloys constitute a class of materials called smart materials which exhibit an unusual property, shape memory effect. The behaviour of these materials is evaluated by the structural changes caused by internal stresses in microscopic scale. Copper based alloys exhibit this property in β-phase field. Shape memory alloys undergo a solid...

of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

A series of alloy systems, in particular copper-based β-phase alloys and NiTi alloys exhibit a peculiar property called shape memory effect. Metastable β-phases of noble metal copper based ternary alloys have commonly bcc structure and homogenise as B2(CsCl) or DO3 (Fe 3Al) type ordered structures at high temperatures. In some cases, L21 (Cu2AlMn)-...

A series of alloy systems exhibit a peculiar property which involves the repeated recovery of macroscopic shape of material at different temperatures. The study of such materials, which are often called smart materials due to their capacity of responding to changes in the environment, is a field of research in rapid evolution. The origin of this ph...

One particular group of materials exhibits a peculiar property called shape memory effect.

The behaviour of shape memory alloys, which exhibit a peculiar property, is evaluated by the structural changes in microscopic scale. Metastable beta phases of copper-based ternary alloys are very sensitive to the heat treatments and transform martensitically from the ordered structures to the long-period layered structures on cooling. Martensitic...

The NixAl1−x alloys exhibit shape memory effect, for which thermoelastic phase transformations are essential, in the composition range of 60<x<65. The analytical studies are very difficult on the thermoelastic phase transformations because these types of transformations exhibit anharmonic behaviour. In order to overcome this difficulty, it is possi...

The solid–solid phase transitions in NiAl alloys occur by the temperature changes and application of a pressure on the system. Both types of transitions are called martensitic transformation and have displacive and thermoelastic characters. Pressure effects on thermoelastic transformation in Ni62.5Al37.5 alloy model have been studied by means of mo...

Interatomic potentials have great importance in the analysis and calculations of some parameters in atomic scale. These calculations are realised by the computer simulation techniques. In the present study, a molecular dynamics (MD) simulation method which allows the system to vary in shape and size was used for the investigation of diffusionless p...

The martensitic transformation behaviour, morphology and transition temperatures in copper-based shape memory alloys are strongly influenced by heat treatments. The effects of various quenching, up-quenching and step-quenching in a water bath 100 °C and in an oil bath at 200 °C have been studied on two shape memory Cu–Al–Ni alloys. The changes at e...

In noble metal copper-based β-phase alloys, which exhibit the shape memory effect, martensitic transformation occurs by lattice invariant shears on close-packed {110}β planes of the matrix, called the basal plane of the martensite. The parent single crystal undergoes the martensitic transformation on cooling in a self-accommodating manner minimisin...

The aging behavior of CuZnAl martensites (Cu-21.62 wt.% Zn-5.68 wt.% Al and Cu-24.98 wt.% Zn-4.43 wt.% Al) at about 297 K was studied by analyzing diffraction line profiles obtained by X-ray diffractometry. For the alloys, the change of the lattice parameters and the tetragonality associated with the aging time at room temperature were investigated...

Shape-memory alloys exhibit super-elasticity when they are deformed at a temperature less than the transformation temperature. The specimen remains in the deformed shape on releasing the strain at this temperature but recovers the undeformed original shape on heating to temperatures over the reverse transformation temperature. As a result of their...

Shape memory alloys exhibit superelasticity when they are deformed in a temperature range where the thermoelastic martensite forms on application of a strain. The martensite persists upon removal of the applied strain, and the alloy recovers the original shape on heating over the reverse-transformation temperature after removing the strain. The β-p...

The martensitic transformation behaviour, morphology and microstructures in copper-based shape memory alloys are strongly influenced by the post-quench heat treatments and ageing. Martensitic transformation initiates at a critical temperature and grows by the formation of martensite variants on cooling up to martensite finish temperature. These all...

The shape memory CuAINi alloys, having a composition near that of Cu 3AI, exhibit disorder-order transition from the disordered bcc p-phase to the ordered pj-phase (D03 type) at high temperatures. Although the P,-phase is a non-equilibrium phase, it nonetheless remains stable at room temperature upon quenching from the high temperature P-phase. At...

The martensitic transformation behaviour, morphology and microstructures in copper-based shape memory alloys are strongly influenced by the post-quench heat treatments and ageing. Martensitic transformation initiates at a critical temperature and grows by the formation of martensite variants on cooling up to martensite finish temperature. These all...

The microstructure of 256 argon atoms located on ideal fcc lattice sites on which periodic boundary conditions have been applied at the vicinity of transition temperature has been investigated. The forces among atoms have been derived from Lennard-Jones potential energy function and the equations of motion of the system have been solved by using th...

The martensitic transformation and the associated mechanical shape reversibility in copper-based shape memory alloys is strongly influenced by quenching and ageing treatments. Ageing of martensite in as-quenched Cu-Al-Ni alloys can result in loss of memory behavior. Structural studies have been carried out to measure the changes in the degree of or...

Stabilization behavior of the martensite in shape memory CuZnAl and CuAlMn alloys has been studied by x-ray measurements and electron microscopy. In these alloys influenced by both quenching and post-quench heat treatments, the degree of stabilization depends on quenching conditions. The stabilization process is mainly due to structural change and...

The compounds Cu2PbBr4, Cu2SnI4, and Cu2PbI4 have been synthesized as stable phases in the CuBr-PbBr2, CuI-SnI2, or CuI-PbI2 binary systems. Cu2PbBr4 is cubic (a0=9.170 A ̊), whereas Cu2SnI4 and Cu2PbI4 are hexagonal with a=9.050, c =9.706 A ̊, and a=8.064, c=15.128 A ̊, respectively. These materials are characterized mainly by a rather high anioni...

PbSnI4 has been prepared from equimolar amounts of PbI2 and SnI2. X-ray and DSC measurements show the material to be uniphase in the temperature range 30 to 400°C; it has a tetragonal structure and melts at 379°C. The electrical conductivity is mainly ionic with an ionic transport number greater than 0.99 at 200°C. Conductivity at room temperature...