Study on Microstructure Evolution and Mechanical Properties of Ti2AlNb-Based Alloy under Canning Compression and Annealing

Abstract

The influence of height reduction on the microstructure evolution and mechanical properties of the Ti2AlNb-based alloy was investigated during canning compression and subsequent annealing. After the annealing treatment, the spheroidized B2 phase grains occurred because of partial recrystallization. Meanwhile, the texture evolution of the B2 phase and O phase were analyzed under the deformation degree, ranging from 25% to 75%. The results show that the mechanical properties of the post-annealed alloys were co-affected by the grain size and Schmid factor of the B2 phase. When the height reduction was less than 25%, the compression strength was mainly affected by the grain size. When the height reduction was higher than 50%, it was mainly dominated by the Schmid factor. When the deformation degree reached 75%, the recrystallized grain size decreased to 0.9 μm. Meanwhile, the Schmid factor of a {110}<001> slip system in B2 phase reduced to 0.34. Therefore, the yield strength of the Ti2AlNb alloy at room temperature increased from 892 MPa in the as-rolled condition to 935 MPa after the canning compression and annealing.

A Review—Additive Manufacturing of Intermetallic Alloys Based on Orthorhombic Titanium Aluminide Ti2AlNb

“…According to [ 3 , 21 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ], a favorable effect on ductility and impact toughness of O-phase alloys results from an increase in the volume fraction and refinement of β(B2)-grain size, the absence of grain boundary α 2 -precipitates and thickening of O-phase plates. An increase of secondary O-phase volume fraction along with a reduction of α 2 -phase and the formation of refined O-phase platelets enhance strength characteristics.…”

The Polythermal Section of Ti-22Al-xNb (30-78at.%Ti) in Ti–Al–Nb System

“…The addition of an appropriate amount of niobium can significantly improve the oxidation resistance, the thermal deformation and hot creep properties of these alloys [3]. Ti 2 AlNb alloys are typical representatives of them [4,5]. The general composition of these alloys is usually Ti-(18-30 at.%) Al-(12.5-30 at.%) Nb.…”