Positive and negative effects of hydrogen on tensile behavior in polycrystalline Fe–30Mn–(6 − x)Si–xAl austenitic alloys

We investigated the tensile properties of Fe–30Mn–(6 − x)Si–xAl (in wt.%, x = 0, 2, 3, 6) austenitic alloys precharged with hydrogen gas at 10 MPa. The Fe–30Mn–6Al alloy showed hydrogen-improved elongation through enhancement of work hardening capacity in the plastic instability condition, although the other alloys did not. This improvement in elongation is considered to be a result of a reduction in stacking fault energy because deformation twinning appeared only in the hydrogen-precharged condition.

Optical micrographs of the fractured specimens (a) without and (b) with hydrogen in the Fe-30Mn-6Al alloy. (c) Bright-field transmission electron microscopy image of the hydrogen-charged Fe-30Mn-6Al alloy. (d) Corresponding diffraction pattern and (f) its key diagram. (f) Dark-field transmission electron microscopy image showing deformation twins. The beam axis is <110>.Figure optionsDownload high-quality image (303 K)Download as PowerPoint slide