Study of rapidly quenched Fe100−xMx crystalline alloys by Mössbauer effect spectroscopy (M=B, C, Al, Si, P)

The rapidly quenched, crystalline, Fe-rich Fe100−xMx system has been studied by 57Fe Mössbauer effect spectrometry. Boron and carbon alloys were found to have regions with cementite local structure. Small amounts of fcc γ-Fe were also observed in some of the cases. Furthermore, almost half of the carbon was concluded to be in interstitial solution. Upon annealing the carbon alloy, the fcc phase disappears to benefit formation of the cementite. In contrast, the alloys with aluminum, silicon, and phosphorous are substitutional solid solutions. After being annealed at 1073 K, they do not show changes in their hyperfine interactions nor in their crystalline structure. However, the lattice parameter of the alloy with phosphorous unexpectedly increased from a value below that corresponding to pure iron to another above it. These results are discussed on the basis of the metalloid solubilities in iron and their atomic sizes.