Research On Mossbauer Spectroscopy Of Fe-V Alloys

M（?）ssbauer spectroscopy has an extremely high energy resolution,which can directly detect the hyperfine interaction between nucleus and external environment of nucleus in samples.When external environment of nucleus changes,the shape,intensity,line width,etc.of M（?）ssbauer spectroscopy will change.M（?）ssbauer spectroscopy has such a wide range of applications that has been described as "the key to reveal the microcosmic mysteries of iron".The changes of composition and temperature affect the microstructure of Fe-based magnetic alloys,including the distribution of solute atoms around Fe atoms,microscopic magnetism and electronic structure.This paper chooses Fe-V alloys as the research object,to study the influence of composition and qunenching temperature on the atomic distribution,microscopic magnetism and spin-electron density of Fe-V alloys by means of transmission M（?）ssbauer spectroscopy.The main results are as follows:Transmission M（?）ssbauer spectroscopies of the alloys are all ferromagnetic sextets under different heat treatment conditions.When the number of V atoms located in the first-nearest-neighbor and the second-nearest-neighbor of Fe atom is n and m respectively,the actual probability C（n,m）has a deviation with the probability P（n,m）calculated by random binomial distribution.With increasing of V content,the degree of deviation between C（n,m）and P（n,m）becomes serious,which indicates alloys have a certain short-range order.Warren-Cowley short-range order parameters α₁,α₂ and α₁₂ of alloys were calculated.With the increase of V content,α₁ turned from negative to positive which indicates V atoms located in the first-nearest-neighbor of Fe atom have a distribution from ordering to partial aggregation.α₂ was always negative,which indicates V atoms located in the second-nearest-neighbor of Fe atom have an ordering distribution;α₁₂ is a small negative number,the absolute value from large to small,which indicates the degree of ordering weakened.At different temperatures,α₁ is positive and has the maximum at 650℃;α₂ is negative and has an absolute minimum at 600℃;α₁₂ is a small negative number with an absolute maximum at 600℃.V atoms located in the first-nearest-neighbor and second-nearest-neighbor of Fe atom lead value of hyperfine magnetic field reduced.With the V content increases,the average value of hyperfine magnetic field decreases linearly,which indicates magnetic moment value of alloys decreases.The shape of between HFD curve and the y=0 are moved to the low field side.The average value of hyperfine magnetic of Fe_0.88V_0.12 alloy with different quenching temperature has little change and has the maximum at 650℃.The peak structure of HFD curve changes obviously with quenching temperature varying.There is a linear relationship between the electron density and the spin density around the Fe nucleus with different coordination.When the position in the nearest neighbor of Fe atom is replaced by the V atom,the change of electron density is linear to the change of the spin density,those linear relationship does not depend on the variation of V content.The electron density at Fe nuclei increases linearly and the spin density decreases linearly with V content increasing.The Mossbauer spectroscopies at different quenching temperatures show that the charge density and the spin density at Fe nucleus still has a linear relationship.