Dislocation motion on octahedral and cube planes in Fe 3 Ge polycrystals

An intermetallic compound of L1₂ ordered Fe₃Ge was examined by compression in bulk at various temperatures and by semi-in-situ compression of a thin foil at room temperature. This alloy is known to show monotonic decrease in yield strength being quite different from the other well-known L1₂ intermetallics. It is shown by stereomicroscopy, Burgers vector analyses and semi-in-situ experiments that ?112? types of slips along the {111} faults may contribute to generate glide dislocations on {001} planes, which eventually act as multiplication sources for the cube slips to govern the essential part of the macroscopic deformation. The yield strength is confirmed to decrease monotonically up to 500?K and rapidly upon approaching the L1₂→D0₁₉ transformation temperature with a drastic increase in the strain rate sensitivity. The strengthening mechanism in this dual phase alloy of Fe₃Ge is discussed in terms of dislocation motion on both octahedral and cube planes by analysing the results of TEM observations with the information of Schmidt factors.