Effect of rolling conditions on the structure and shape memory properties in Fe-Mn-Si alloys

A. DRUKER; A. BARUJ; J. MALARRÍA

Rio de Janeiro, Brasil

Conferencia; 11th International Conference on Advanced Materials (ICAM 2009); 2009

SBPMat, Brazil-MRS

Lattice defects play an important role in controlling the ¥ã¡æ¥åmartensitic transformation in shape memory ferrous alloys. This work focuses on the relation between various rolling and annealing processes, the resulting microstructure, and strain recovery of two Fe-Mn-Si alloys with different stacking fault energy. Rolling experiments carried out at temperatures in the 20¨¬C to 1000¨¬C range, give rise to quite different microstructures varying from a high dislocation density to a structure containing only a few isolated dislocations. In addition, annealing temperature has a very important influence not only on the dislocation arrays but also on the stacking faults remaining in the austenite, whose density depends on the SFE value for the alloy. In the frame of the processing parameters selected for this work (i.e. roll speed and degree of deformation values) rolling at intermediate temperatures and annealing at temperatures of 600¨¬C seems to be the most appropriate method to obtain a microstructure favorable for a nearly full degree of shape recovery.¥ã¡æ¥åmartensitic transformation in shape memory ferrous alloys. This work focuses on the relation between various rolling and annealing processes, the resulting microstructure, and strain recovery of two Fe-Mn-Si alloys with different stacking fault energy. Rolling experiments carried out at temperatures in the 20¨¬C to 1000¨¬C range, give rise to quite different microstructures varying from a high dislocation density to a structure containing only a few isolated dislocations. In addition, annealing temperature has a very important influence not only on the dislocation arrays but also on the stacking faults remaining in the austenite, whose density depends on the SFE value for the alloy. In the frame of the processing parameters selected for this work (i.e. roll speed and degree of deformation values) rolling at intermediate temperatures and annealing at temperatures of 600¨¬C seems to be the most appropriate method to obtain a microstructure favorable for a nearly full degree of shape recovery.