EFFECT OF ANNEALING TEMPERATURE ON THE MICROSTRUCTURE AND HARDNESS OF Fe-Mn-Si-Cr- Ni-Co SHAPE MEMORY ALLOY PROCESSED BY WIRE DRAWING

摘要

Stainless shape memory ailoys (SMA's) have been studied since the 90's. The Fe-Mn-Si-Cr-Ni-Co SMA used in this work was processed by wire drawing varying the area reductions, AR's (14%, 39% and 57%) and annealing temperature from 350°C to 1050°C during 1 hour. The microstructural characterization was performed by optical microscopy (OM), scanning electron microscopy (SEM) and Vickers hardness testing. The results showed that the increase of area reduction promoted increase in hardness for the cold drawn and annealed conditions. Results show that the precipitation became noticeable at 450°C and 550°C for samples with AR=39% and 57%, respectively.