Fabricating Ti2AlNb sheet with high tensile strength and good ductility by hot packed rolling the spark plasma sintered pre-alloyed powder

Abstract

In this work, a novel “spark plasma sintering (SPS) of pre-alloyed powder followed by a hot packed rolling” method is proposed to fabricate the Ti2AlNb sheet. Ti2AlNb sheets with high tensile strength and good ductility are obtained without any post heat treatment. Ti2AlNb compact is first prepared by SPS of the pre-alloyed powders. The compact sintered at 1060 °C consists of only B2 phases with an average grain size of 25.88 μm. No α2 phase forms after rolled at 1030 °C and the B2 grain size increases by increasing the rolling passes because of the fast grain growth of B2 grains. Numerous ultrafine O phases precipitated inside the B2 matrix after cooled in air, and they contribute to the excellent strength and ductility of the sheets. The mechanical property tests showed that the sheets rolled by 2 passes (thickness reduction: 42% + 42%) and 4 passes (30% + 21% + 21% + 21%) had the maximum tensile strength of 1239.03 MPa and the maximum elongation of 9.49%, respectively. All the rolled sheets presented ductile fracture mode with numerous dimples on the fracture surface.