Mössbauer spectroscopic and crystal structure investigation of the Fe_0.7-xTi_xAl_0.3 alloy system

We describe a combination of Mössbauer spectroscopic and X-ray structural studies on the alloy system Fe_0.7-xTi_xAl_0.3 where x = 0, 0.05, 0.1, 0.2, 0.3 and 0.35. The dependence of the Mössbauer hyperfine parameters and the lattice constant on x are determined, and a comparison is made to the known behavior of metallic Fe-Al-T alloys. X-ray diffraction patterns indicate that all the samples are single phase with body center cubic structure. The lattice constant increases linearly with increasing Ti concentration. Room temperature Mössbauer studies show magnetic ordering for small x and paramagnetic behavior for large x. The Mössbauer spectra were fitted by a distribution of magnetic hyperfine fields for small x and two singlets were added for large x. Analysis of the X-ray and Mössbauer results show that the Ti atoms preferentially occupy the Fe site. The average hyperfine field and isomer shift decreased with increasing Ti concentration. The results are related to local environment effects on the hyperfine interactions.