| High temperature titanium alloy has the excellent advantages of light weight, heat resistance, high strength, becoming one of the aerospace engine and automotive lightweight heat-resistant structural component of the most promising high temperature materials. After many years of developmentat home and abroad, has formed a Ti-Al-Sn-Zr-Mo-Si-Ti alloy system, but there is no mature 600℃high temperature titanium alloy application. To date, researches on this alloy mainly focus on wrought process.Unfortunately, little attention has been paid to the casting method. The effect of Three kinds of alloy element content Si, Mo, Y oncasting alloy microstructure and properties has been studied in this paper.Firstly, according to the empirical formula of the aluminum equivalent, design 9 kinds of alloy composition byadjustting content of Si, Mo, Y, uniform composition of titanium alloy was prepared by vacuum arc melting technique of. By means of optical microscopy, X-ray diffraction, scanning electron microscope equipped with an energy spectrum analysis) experimental equipment on the as cast microstructure of the alloy were analyzed by casting microstructure are α/β basket-like microstructure.Three kinds of alloy element content Si,Mo,Ychanges did not changalloy nearαalloy microstructure.Effects of three kinds of alloy element content Si,Mo,Y was different in as cast microstructures and mechanical properties of titanium alloys by state. It is found that with the increase of Si content, the microstructure of the alloy increases gradually, the Vickers hardness slow small, mass fraction of 0.25% strength at room temperature is the best, KICofthe fracture toughness is 54.3MPa·m1/2,room temperature compression performance in 0.15% is the best. Compared to the Mo content of different alloy microstructure and properties found Mo content increased refinement of the microstructure of the alloy, increasing the Vickers hardness of the alloy, improve the room temperature fracture toughness and compressive properties. With the increase of the content of Y, Y2O3 precipitates in the alloy gradually increased, so that the organization can be refined significantly, increase the hardness of the alloy, mass fraction of 0.7% is hardness reaches the peak value HV505.8 and room temperature fracture toughness of the alloy and the compression performance is also obtained the strengthening, the 0.7% alloy compressive strength and yield strength is much higher than that of the other components of the alloy, but quick break should be disguised to poor.Mechanical properties of 9 kinds of alloys were compared.Selectting Ti-5Al-4Sn-2Zr-1Mo-0.25 Si,Ti-5Al-4Sn-2Zr-3Mo-0.25 Si,Ti-5Al-4Sn-2Zr-1Mo-0.25Si-0.7Y of three kinds of good mechanical properties of the alloy, the research in 950-1010℃, 0.01s-1-1s-1 range high temperature compression heat deformation behavior. This high temperature titanium alloy is basically a negative temperature sensitive materials and the positive strain rate sensitive material, namely with the temperature decrease and increase of strain rate, the flow stress increased.Increases,decrease and stabilize of the flow stress force curve the process corresponds to the strain hardening and strain softening process of alternating control and dynamic balance process. Establish the hyperbolic sine function of Ti-5Al-4Sn-2Zr-1Mo-0.25Si-0.7Y alloy constitutive equation of. In the hot deformation process,the deformation temperature and strain rate has different deformation areas on the microstructure of the alloy. |
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