Unveiling segregation-induced evolution in phase constitution of Cu-containing high-entropy alloys

• A theoretical investigation of Cu segregation effect on phase constitution, magnetic, and mechanical properties of FeCoNi(CumAl)(x) high-entropy alloys is presented. Results show that the homogenous FeCoNi(Cu1.0Al)(x) only exists as a single face-centered cubic phase at arbitrary temperatures. The level of Cu-segregation determines the phase evolution amongst inhomogeneous single phase (0.75 <= m < 1.0), duplex phase (m << 0.75), and triple phase (m approximate to 0.75). Our results reproduce the observation. Only face-centered cubic phase can be formed for FeCoNi(CumAl)(x) with either rather low or extreme high content of (CumAl) even though the segregation occurred. The Cu addition lifts the total magnetic moments by enhancing the local magnetic moment of Fe, Co and Ni. The serious Cu segregation in the duplex-phase HEAs induces the decrease of ductility of fcc and bcc phases. The increasing Cu enhances the strength of Cu-rich fcc phase and the decreasing Cu weakens that of Cu-poor bcc phase.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

High-entropy alloys

Cu segregation effect

Phase constitution

First-principles calculations

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