Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 25: Poster Session

MM 25.33: Poster

Wednesday, March 29, 2006, 15:30–17:30, P4

Shape Memory Mechanism and Microstructural Analysis of Martensitic Transitions in Copper Based Alloys — •Osman Adiguzel — Firat University Department of Physics, 23169 Elazig/Turkey

The copper-based alloys can also exhibit the shape memory effect within a certain range of compositions. These alloys have bcc-type disordered structure at high temperatures and undergo the martensitic transition on cooling. In the case of reversible memory effect, forward and reverse transformations occur in the characteristic temperature intervals. Shape memory is related to the elastic behaviour of these materials depending on the temperature in the characteristic temperature ranges. If these alloys are deformed in martensitic condition, they keep the deformed shape, when the stress is removed, and furthermore, the deformation disappears and the material spontaneously returns to the original phase on heating over the austenite finish temperature. These alloys are also called thermoelastic materials due to this behaviour. Martensitic transformations occur by two or more lattice invariant shears on a {110}-type plane of austenite matrix which is basal plane or stacking plane of martensite. Martensite phase has the unusual layered structures which consist of an array of close-packed planes with complicated stacking sequences called as 3R, 9R or 18R martensites depending on the stacking sequences on {110}-type planes of the ordered lattice. Key Words: Shape memory effect, martensite, layered structures