Manufacture-friendly nanostructured metals stabilized by dual-phase honeycomb shell

Abstract

Refining grains to the nanoscale can greatly enhance the strength of metals. But the engineering applications of nanostructured metals are limited by their complex manufacturing technology and poor microstructural stability. Here we report a facile “Eutectoid element alloying→ Quenching→ Hot deformation” (EQD) strategy, which enables the mass production of a Ti6Al4V5Cu (wt.%) alloy with α-Ti grain size of 95 ± 32 nm. In addition, rapid co-precipitation of Ti2Cu and β phases forms a “dual-phase honeycomb shell” (DPHS) structure along the grain boundaries and effectively stabilizes the α-grains. The instability temperature of the nanostructured Ti6Al4V5Cu alloy reaches 973 K (0.55Tm). The room temperature tensile strength approaches 1.52 ± 0.03 GPa, which is 60% higher than the Ti6Al4V counterpart without sacrificing its ductility. Furthermore, the tensile elongation at 923 K exceeds 1000%. The aforementioned strategy paves a new pathway to develop manufacture-friendly nanostructured materials and it also has great potential for application in other alloy systems.