Temperature Titanium Alloy Ti62421s Organizational Performance

Ti62421s titanium alloys is a new nearlyα-titanium alloys, self-study designed by Baoji Titanium Industry Co, Ltd, which has a low density, high strength, remarkable resistant to high temperature and corrosion, and good fatigue performance, and so on.In this paper, the effecting of T (α+β)/βphase transition point of Ti62421s titanium alloys,the hot deformation behavior and the heat treatment on mechanical properties and microstructure of the alloy at room temperature and high temperature were systematically investigated by optical microscope, differential scanning calorimeter (DSC), X-ray diffraction instrument, scanning electron microscope, Energy-dispersive X-ray spectroscopy, transmission electron microscope, thermal simulation machine and mechanical properties testing machine. The main conclu-sions are as follows:(1) T(α+β)/βphase transition point of Ti62421s alloys was studied by the calculation method, differential scanning calorimetry and continuous heating metallographic method, and T (α+β)/βphase transition point of Ti62421s alloy is 1000℃.(2) The thermal deformation behavior of titanium alloy was studied by the thermal/mechanical compression simulation experiment, analysing the effect of thermal deformation parameters on flow stress of the alloy during high temperature deformation, and combining with hot compre-ssion stress-strain curves, material constants of high temperature defor-mation of the alloy was obtained, and high temperature deformation flow stress constitutive equations was established. The results show that:the flow stress increases with increase deformation temperature, and decrease with increase the strain rate.(3) In the two-phase region, the lower the strain rate, the more obvious the globalization of original a phase when the deformation temperature is. When strain rate is constant, the higher deformation temperature, the more obvious martensite transformation during water quenching after deformation. At a high strain rate of 10s-1, the alloy of the true stress-true strain curves appear a distinct stress peak when the deformation temperature higher than 980℃(including 980℃), subse-quently, a sharp decline in the stress turns up or the phenomenon of discontinuous yielding occurs. The higher the temperature, and strain rate, the more obvious phenomenon of discontinuity yielding during materials compressive deformation.(4) The processing map of Ti62421s alloy was firstly established on the basis of Dynamic Material Modeling(DMM). The results showed an optimal parameter being:T=980℃,ε= 0.01～0.1s-1.(5) The paper also studied that the effect of solution temperature and aging temperature on mechanical properties of Ti62421s titanium alloy at room temperature, and high temperature. The results of room temperature test show that:in the two-phase region, with the solution temperature increasing,a phases of the alloy reduce, butβtransformation phases increase; In the singleβ-phase region, it is the single Netsβ-transformation organization; With the aging temperature increasing,α-phase grow and then dissolve. With the solution temperature and aging temperature increasing, in theβ-transformation phases the content of Al increase. With the solution temperature increasing, the strength and area reduction increases and then decrease, the elongation decrease. After solution treatment at 980℃for 1h and aging at 550℃for 8h for Ti62421s alloy, the tensile strength, elongation and area reduction for the alloy are 1077.04 MPa,1048 MPa,13.6%,26.02% respectively, showing the best combination of strength and plasticity.High temperature tensile test results show that:in the solution temperature range, with the solution temperature increasing, the tensile strength and yield strength increase and then decrease, the elongation and area reduction decrease and then increase. With the tensile test temperature increasing, tensile strength and yield strength decrease, elongation and area reduction increase.