Chemical evolution-induced strengthening on AlCoCrNi dual-phase high-entropy alloy with high specific strength

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Quaternary AlCoCrNi alloy was designed by removing the heavy constituent of Fe from the dual-phase AlCoCrFeNi high-entropy alloy to achieve low density with good mechanical properties. The AlCoCrNi alloy exhibited a nano-scale dual-phase structure consisted of Cr-rich A2 and Ni(Co)-Al-rich B2 phases with a high degree of coherence in both dendritic and interdendritic regions. In particular, the Ni(Co)-Al-rich B2 phase revealed the non-stoichiometric composition between the Ni and the Al, which deviated with the Ni-Al-rich B2 phase with a stoichiometric composition in the previous AlCoCrFeNi high-entropy alloy. The chemical evolution in the constituent phases strongly affected the mechanical properties of the dual-phase high-entropy alloy. Based on these microstructural features of the AlCoCrNi alloy, the mechanical properties were systematically investigated at wide temperature ranges.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AlCoCrNi alloy is designed by modulating from the AlCoCrFeNi HEA. </LI> <LI> Nano-scaled Cr-rich A2 and Ni(Co)Al-rich B2 phases are formed in ID and DR regions. </LI> <LI> The Ni(Co)Al-rich B2 phase exhibits non-stoichiometric composition between Ni and Al. </LI> <LI> The chemical evolution on B2 phase induces a strengthening of the AlCoCrNi alloy. </LI> <LI> The alloy with a low density of 6.9 gcm<SUP>−3</SUP> reveals superior specific strength at wide temperature ranges. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>