Microstructural evaluation on shape recovery in stainless Fe-Mn-Si-Cr-Ni-Co SMA processed by wire drawing

Abstract

The effect of the microstructure on the shape recovery in stainless Fe-8Mn-5Si-13Cr-6Ni-12Co shape memory steel (SSMS) was evaluated using tensile tests and reversion temperature of 600°C for a pre-strain of 4%. The tests were performed for a solution treated and annealed conditions at different temperatures after wire drawing of 57% area reduction. The best total shape recovery (TSR) was 83% for a sample deformed and annealed at 850°C. It was concluded that the elastic (or, superelastic) shape recovery (ESR) is high when the austenitic matrix strength is high surpassing the value of shape recovery due to memory effect (SR) and once the austenitic matrix becomes softer, the contribution of SR increases and that of ESR decreases.

The Influence of Microstructure and Mechanical Resistance on the Shape Memory of Ecae Processed Stainless Fe-Mn-Si-Cr-Ni-Co Steel

“…Inversely, the increase in the mechanical resistance promotes a proportional increase of the elastic shape recovery (γ ↔ ( transformation), since atoms in solid solution, deformation defects and precipitates prevent pseudo-plastic deformation. This behaviour has been observed in different stainless shape memory steel types, as shown in previous works developed by our research group 12,29…”

Strain Hardening of Carbon Steel During Wire Drawing

“…To calculate the friction coefficient many method had been proposed: for example, Leu 7 used a model of plastic hemispherical contact against a rigid flat and described the deformed shape as the fractional profile of an ellipsoid, while Ajiboyeet al 8 performed an ANOVA analysis comparing two regression models to predict the shear friction factor at the punch interface. Similar models and experimental analyses are presented by Parida et al 17,18 , Souza et al 13 and Andrade et al 14 . The principal aim of this paper is to compare the hypothesis of strain hardening used by Avitzur in the model proposed in 1 for the calculation of the force in wire drawing with the real behaviour of a carbon steel subjected to an industrial drawing process.…”

“…A series of tensile tests for a 0.8 carbon steel wire in various steps of a complete drawing process were carried out, according to the industrial practise 13,14,15 . From the results of the tests it was possible to evaluate deformation and strain hardening effects on the mechanical characteristics of materials 11, 12,16 .…”

Key Factors Achieving Large Recovery Strains in Polycrystalline Fe–Mn–Si‐Based Shape Memory Alloys: A Review

“…In 1990, Otsuka et al further developed stainless Fe – Mn – Si–Cr–(Ni) SMAs, such as Fe–28Mn–6Si–5Cr, Fe–20Mn–5Si–8Cr–5Ni, and Fe–16Mn–5Si–12Cr–5Ni . Furthermore, effects of other alloying elements such as interstitial atoms, rare earth elements, copper, and cobalt on SME were investigated in the Fe – Mn – Si‐based SMAs. In addition to the SME, a lot of researches on factors influencing the recovery stress of Fe – Mn – Si‐based SMAs have also been done .…”