A significant increase in the hardness of nanotwinned titanium alloys prepared via the martensitic phase transformation

Abstract In this work, a nanotwinned structure of a two-phase titanium (TC21) alloy was prepared via the martensitic phase transformation method. The TC21 alloy forms initially a single phase β when the temperature reaches 1050 °C. Then, it transitions into an orthorhombic martensite (α“) material when quenched in water. After tempering at 500 °C, the martensite transforms into a high-density nanotwinned α phase material. The hardness of the nanotwinned alloy is 25% higher than that of the TC21 raw material.