Effect of rare-earth addition on the shape memory behavior of a FeMnSiCr alloy

The influence of rare-earth (RE) addition in a wide concentration range of 0.032-0.46 wt.% on the shape memory effect (SME) of a Fe-25Mn-6Si-5Cr alloy was investigated in the present pacer. The results show that the shape recovery rate (eta) is significantly enhanced in a certain range of RE content, e.g. less than or equal to about 0.3 wt.%. In particular, the FeMnSiCr-0.16RE alloy achieves almost 100% recovery, after only two cycles of training. The SME improvement is presumably attributed to a reduction in the stacking fault energy (SFE) and the grain size refinement of austenite matrix. However, an opposite effect was found in the alloy containing 0.46% RE, of which the SME is even worse than that without RE, and the RE precipitate particles were observed at grain boundaries and within the grains as well. (C) 2002 Elsevier Science B.V. All rights reserved.