Effect Of Deformed Microstructure On Mechanical Properties Of Ti-22al-25nb Alloy

Effect of the deformed microstructure on mechanical properties of an orthorhornbic (Ti(2)AINb) based alloy of Ti-22Al-25Nb (mole fraction, %) has been investigated. It was found that the deformed microstructures in different portions of a free forged rod with diameter of 30 mm were quite different and thus resulted in the different mechanical properties after the same subsequent heat-treatment. One deformed microstructure with less primary alpha(2)/O particles and a larger and equiaxed B2 grains resulted in poor RT ductility, but the other one with a relatively larger amount of the primary alpha(2)/O particles and non-equiaxed B2 grains had good combination of the tensile strength and ductility both at RT and 650 degrees C. It was also found that two different deformed microstructures were obtained for the hot rolling plates with thickness of 3 min even processed under an identical nominal rolling and the same post-deforming heat treatment conditions. One only has 3.5% of RT tensile elongation and the other up to 8%.