Phase Transitions and Elementary Processes in Shape Memory Alloys

Osman Adiguzel

doi:10.4028/www.scientific.net/AMR.1101.124

Paper Titles

Effect of Grain Refinement on Shape Memory Properties of Cu-Al-Mn SMAs
p.104

The Influences of Ru Seed Layer Microstructure on Structural Properties of CoCrPt-SiO₂ Perpendicular Media
p.108

Oxygen Impurity in Germanium Single Crystals Determination by Infrared Spectrometry
p.115

Morphological Transformations of Top Electrodes on YMnO₃ Caused by Filamentary Resistive Switching in the Oxide Matrix
p.120

Phase Transitions and Elementary Processes in Shape Memory Alloys
p.124

Effects of Aluminum Addition on Microstructural Characteristics in Modified Coated Nickel-Based Superalloy, GTD-111, by Arc Melting
p.129

Preparation of LiMn₂O₄ Microstructure by Low Temperature Solid-State Reaction for Cathode Material
p.134

Morphological and Dimensional Properties of Colloidal Silver Nanoparticles Prepared under Microwave Irradiation
p.138

Electrochemical Oxidation of Dissolved Carbon Monoxide on Rotating Disk Electrodes and Micro-Electrodes
p.144

HomeAdvanced Materials ResearchAdvanced Materials Research Vol. 1101Phase Transitions and Elementary Processes in...

Phase Transitions and Elementary Processes in Shape Memory Alloys

Abstract:

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 facilitated by a displacive transformation known as martensitic transformation. Shape memory effect refers to the shape recovery of materials resulting from martensite to austenite transformation when heated above reverse transformation temperature after deforming in the martensitic phase. These alloys also cycle between two certain shapes with changing temperature.Martensitic transformations occur with cooperative movement of atoms by means of lattice invariant shears on a {110} - type plane of austenite matrix which is basal plane of martensite.Copper based alloys exhibit this property in metastable β-phase field. High temperature β-phase bcc-structures martensiticaly undergo the non-conventional structures following two ordered reactions on cooling, and structural changes in nanoscale level govern this transition cooling. Atomic movements are also confined to interatomic lengths due to the diffusionless character of martensitic transformation.