Measurement of the Anisotropy of Young’s Modulus in the γ’-Fe4N Phase on Nitrided Steel Using the Nanoindentation Method

The Young’s modulus of the γ’-Fe 4 N phase on steel measured by the nanoindentation method exhibited the highest along ⟨100⟩ direction and the lowest along ⟨111⟩ direction, opposite to that of the austenite (γ) phase. The pop-in stress in the nanoindentation test was the highest along ⟨111⟩ and lowest along ⟨110⟩ in the γ’ phase. This trend are consistent with theoretical prediction, supporting the reliability of the anisotropy of Young’s modulus measured using the nanoindentation method.