48 research outputs found
Three-dimensional atom probe analysis of boron segregation at austenite grain boundary in a low carbon steel - Effects of boundary misorientation and quenching temperature
Natural-mixing guided design of refractory high-entropy alloys with as-cast tensile ductility
Multi-principal-element metallic alloys have created a growing interest that
is unprecedented in metallurgical history, in exploring the property limits of
metals and the governing physical mechanisms. Refractory high-entropy alloys
(RHEAs) have drawn particular attention due to their (i) high melting points
and excellent softening-resistance, which are the two key requirements for
high-temperature applications; and (ii) compositional space, which is immense
even after considering cost and recyclability restrictions. However, RHEAs also
exhibit intrinsic brittleness and oxidation-susceptibility, which remain as
significant challenges for their processing and application. Here, utilizing
natural-mixing characteristics amongst refractory elements, we designed a
Ti38V15Nb23Hf24 RHEA that exhibits >20% tensile ductility already at the
as-cast state, and physicochemical stability at high-temperatures. Exploring
the underlying deformation mechanisms across multiple length-scales, we observe
that a rare beta prime precipitation strengthening mechanism governs its
intriguing mechanical response. These results also reveal the effectiveness of
natural-mixing tendencies in expediting HEA discovery.Comment: 31 pages, 4 figures in the maintext; 2 tables and 18 figures in the
supplementary informatio