Effect of Microstructure on Mechanical Properties of a New High Strength Beta Titanium Alloy

Abstract:

A new high strength titanium alloy include elements Cr, Fe Mo,W and Al was designed in order to achieve an excellent combination of ultra-high strength and good fracture toughness. Both the α/β and β heat treatment were intbilletuced to study the effect of microstructure on mechanical properties of alloy in this work. The result shows that the alloy with α/β solution plus aging treatment which composed of a mixture microstructures obtained a few equiaxed or short billet-like primary α phase and fine lamellar secondary α phase has excellent combination of ultra-high strength and good fracture toughness. The corresponding tensile strength is the superior strength about 1400MPa and fracture toughnesses K_IC is 50.7 Mpa.m_1/2. Compared with α/β heat treatment, the alloy with β region heat treatment presents representative Widmanstiitten structure which has higher fracture toughnesses and lower strengths than the mixed microstructures.

Key words:Microstructure;high strength titanium alloy;Mechanical property