Effect of nitrogen and carbon on electron exchange and shape memory in a Fe-Mn-Si base shape memory alloy

The influence of carbon and nitrogen on the electronic properties and shape memory in Fe62Mn16Si10Cr9Ni4 (at.%) alloy was studied by means of conduction electron spin resonance (CESR) and dilatometry. It was shown that carbon causes localization of electrons at the atomic sites and clustering of substitutional atoms, whereas nitrogen leads to an increased concentration of free electrons at the Fermi surface and assists in a more homogeneous distribution of substitutional solutes. A larger recovered strain is found in the nitrogen-doped alloy in comparison with the carbon one. The role of carbon- and nitrogen-caused change in the electronic properties, short range atomic order and strengthening on the shape memory effect is discussed