The microstructure development in a Zr-enriched Ti–Zr–Al–Nb alloy during heat treatment for superior strength-ductility combination

In this work, a Zr-enriched Ti-Zr-Al-Nb alloy was proposed and prepared. The development of microstructure during heat treatment was investigated, and the tensile properties were compared. The results showed that the martensite phase that formed in quenching, with very a little β phase remained, decomposed incompletely during aging. The partially decomposed HCP-structured phases exhibited a promising solid-solution strengthening effect. The yield strength slightly decreased with the increment of aging temperature, mainly due to the fact that the volume fraction of the resultant α 2 ′ phase increased with relatively low solid-solution strengthening effect. Via quenching and then aging, the alloy exhibited a superb strength-ductility combination. The tensile yield strength and ultimate strength of the alloy could reach, respectively, above 1350 MPa and 1430 MPa, while the maximum elongation reached 10.3%.