Abstract
In this study, Fe-28Mn-6Si-5Cr alloys (cold-drawn wires) were annealed at 673 K, 773 K, 873 K, 973 K, 1073 K, 1173 K and 1273 K to reform the microstructure and enhance shape memory effect (SME). The specimens were investigated with electron backscatter diffraction analysis, X-ray diffraction line profile analysis, Vickers hardness test and bending test. These analyses and hardness test indicated recrystallization behavior of the alloys occurred as follows: recovery (above 673 K) → recrystallization (above 883 K) → grain growth (above 1073 K). Bending test showed the specimens annealed at 873 K and 973 K had the excellent SME. In contrast, the specimen at lower temperatures decreased SME because of less existence of austenite phase before deformation. The specimen at higher temperatures decreased SME because of the recrystallization and the grain coarsening, i.e., grain growth. The dislocation annihilation and rearrangement (recovery) encouraged γ ↔ ε transformation and enhanced SME.
