Structural Effects of Thermomechanical Processing on the Static and Dynamic Responses of Powder Metallurgy Fe-Mn-Si Based Shape Memory Alloys
Fe-14Mn-6Si-9Cr-5Ni (wt. %) shape memory alloys (SMAs) were produced by powder metallurgy (PM) combined with Mechanical Alloying (MA). The specimens were pressed and sintered under Ar atmosphere from as blended powders as well as from mixtures of as blended and 10, 20, 30 and 40 vol. % MA’ed powders, respectively. The five groups of sintered specimens were hot-rolled, spark-erosion cut and solution treated at five temperatures (923, 1023, …, 1373K/ 300 s/ water). Tensile loading-unloading tests were performed in order to obtain stress-induced martensite at different pre-straining degrees. The static responses of the twenty five types of specimens were evaluated by means of the surface areas under unloading curve (E2) and between loading and unloading curves (E1) which were used for determining static internal friction, Q-1. The dynamic responses of the undeformed specimens were determined by Dynamic Mechanical Analysis (DMA) performed at room temperature with a three-point-bending specimen holder in strain sweep mode. The structure of the twenty five specimens was analyzed X-ray diffraction. The effects of MA fraction were correlated with static and dynamic responses via structural changes.
E. Mihalache et al., "Structural Effects of Thermomechanical Processing on the Static and Dynamic Responses of Powder Metallurgy Fe-Mn-Si Based Shape Memory Alloys", Advances in Science and Technology, Vol. 97, pp. 153-158, 2017