Ultrastrong and ductile BCC high-entropy alloys with low-density via dislocation regulation and nanoprecipitates

The high strength is a typical advantage of body-centered-cubic high-entropy alloys (BCC -HEAs). However, brittleness and weak strain-hardening ability are still their Achilles' heel. Here, extraordinary strength together with good tensile ductility are achieved in (Zr0.5Ti0.35Nb0.15)(100-x)Al-x alloys (at.%, x = 10 and 20) at room temperature. Relatively low densities of less than 6 g/cm(3) are exhibited in these alloys. Designing nanoprecipitates and diversifying dislocation motions are the keys to achieving such salient breakthrough. It is worth noting that the tensile strength of 1.8 GPa in (Zr0.5Ti0.35Nb0.15)(80)Al-20 alloy is a record-high value known in reported BCC -HEAs, as well as a tensile strain over 8%. Furthermore, the maximum strain of similar to 25% in (Zr0.5Ti0.35Nb0.15)(90)Al-10 alloy can challenge existing limit value, and is accompanied with a tensile strength of 1.2 GPa. The current work does not only provide novel ultra-strong and tough structural materials with low density, but also sheds new light on designing BCC -HEAs with attractive performances and strain-hardening ability. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

Extraordinary strength and good tensile ductility are achieved in (Zr0.5Ti0.35Nb0.15)(100-x)Al-x alloys at room temperature. The relatively low densities exhibited in these alloys make them attractive structural materials. Designing nanoprecipitates and diversifying dislocation motions play key roles in achieving such breakthrough.