材料期刊网

The aims of the work were to study the effect of Ge (0-6wt. %) on the paramagnetic-antiferromagnetic transition and martensitic transformation of Fe-Mn alloy using the susceptibility, microstructure examination, X-ray diffraction (XRD) and lattice parameter measurement. Ge lowers the Neel temperature, TN, and enhances the mag-netic susceptibility X, changing the Pauli paramagnetism above TN to paramagnetism state obeying the Curie Weiss law, which is essentially similar to that of γ-Fe-Mn alloys containing Al or Si; Ge depresses γ → ε martensitic transformation, which attribute to Ge increasing the stacking fault energy; Moreover, Ge increases the lat-tice parameter of 7 phase, and low content Ge increases the lattice parameter of γphase more than that of high Ge content. Comparing Ge(4s2 4p2 ) with Si(3s2 3p2 ) and Al(3s2 3p1), which have the same outer-shell of electron structures, we found that their effects on the martensitic transformation of Fe-Mn alloy are completely different. The result suggests the outer-shell of electron is not the main factor of governing the Ms temperature of Fe-Mn alloy although it is essential in the alloy's antiferromagnetic transition. The relation among the Ms temperature, stacking fault energy and lattice parameter of austenite, has been discussed in brief.