The Microstructure And Mechanical Properties Of Ti-Al-V-Fe-O Lowcost Titanium Alloy

Titanium alloy has advantages of low density, low specific strength, corrosionresistance, high temperature performance and so on, which has been widely usedin the aerospace and military industries. However, its excessive costs seriouslyrestrict the wide use of titanium alloy in various fields. Therefore, this subject isfocusing on the research of high strength of titanium alloys with low costs.According to the latest development of the low cost of titanium alloy at homeand abroad, several groups of Ti-Al-V-Fe-O based on Ti-6Al with low cost of alloyhave been designed. The transition temperature of β-phase in each alloy has beenmeasured by calculation method and DSC thermal analysis after the obtaining theingot and the microstructures of different alloy have been analyzed by means ofthe optical microscope, scanning electron microscope and X-ray diffraction.Meanwhile, Mechanical properties in different conditions of alloy were measuredby using the electronic universal tester, Micro hardness tester and the dynamicthermal simulation test machine.The results of measuring the tensile properties and hardness of each alloyindicate that:(1) V, Fe has a strengthening effect on the yield strength and tensilestrength; with the increase of V, Fe content, yield strength and tensile strengthincrease accordingly;(2) When the Fe element content increased in a certain range,the elongation of the alloy decreased;(3) The V element has an obvious refinementeffect on the microstructure of titanium alloys, when the V element increased, therate of the alloy extension will be slightly higher;(4) When the O elementincreased, the strength and hardness of the alloy have greatly improved and theelongation and elastic modulus declined dramatically. So the oxygen content mustbe strictly controlled in a certain range to meet the requirements of strength andplasticity of alloy.The Ti-6Al-3V-Fe-0.26O alloy was studied by using a Gleeble-1500thermomechanical simulator at different temperatures and different compression ratiocompression tests under high temperatures. The results showed that: when thealloy was studied by high temperature compression, flow stress first increasedrapidly as the strain increased and reached the peak. When the strain increasedfurther, the flow stress decreased gradually until it reached the steady statebetween950～1000℃;with the increase of deformation temperature, the peak andsteady-state stress decreased and the peak strain decreased accordingly. While in 1050~1100℃, the peak and steady-state rheological curves of stress were close tothe fixed figure with the increase of deformation temperature.