The modeling of the deformation behavior of Cu-Al-Nb shape memory alloys containing primary particles

Jozef Lelatko 1Henryk Morawiec 

1. Silesian University of Technology, Department of Materials Science, Krasińskiego 8, Katowice 40-019, Poland

Abstract

The deformation properties of a new group of the Cu-Al-Nb (up to about 8 wt.% Nb) base alloys exhibiting the shape memory effect at elevated temperature were the subject of this work. Niobium, which solubility in copper is low, exists in these alloys in a form of primary precipitates of intermetallic phases, mainly the Nb(Cu,Al)2 Laves phase. The carried out studies have shown that the primary precipitates of the intermetallic phases on the niobium base play a basic role in a simultaneous strengthening and increase in plasticity of these alloys.
Models elaborated for the metal-matrix composite materials were modified in order to enable the control of the deformation properties of shape memory alloys containing significant number of primary particles.
The modified model of the continuum mechanics approach based on the effective medium approximations and supplemented by the dislocation plasticity model enabled analysis of the deformation course of the Cu-Al-Nb type alloys. By comparing the simulated and experimental stress – strain curves for these alloys, the effect of particle size, volume fraction and their elastic properties on the deformation response are given. With this model it can be shown that the increase in the alloy hardening during deformation results from the presence of hard and elastic particles in the martensite matrix as well as dislocations formed at the partial accommodation of the residual stresses created during the alloy quenching.

 

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Presentation: oral at E-MRS Fall Meeting 2005, Symposium C, by Jozef Lelatko
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-19 11:12
Revised:   2009-06-07 00:44