Study On Hot Deformation Behavior And Processing Map Of Titanium Alloy β-CEZ

With the rapid development in the field of high-speed aircraft, the demand for highstrength lightweight materials also continued to rise, high-strength titanium alloy is in line with this demand. β titanium alloy which can not only by heat treatment to achieve the desired strength and toughness to match, but also has good cold and hot processing performance, is the main development direction of high-strength titanium alloy in domestic and foreign.The research object in this paper is β-CEZ titanium alloy, according to the thermal simulation compression test and microstructure observation, study on thermal deformation behavior and microstructure evolution. Established the constitutive model based on Arrhenius equation and artificial neural network, and simulate the compression test with finite element. Established the processing map based on dynamic material model, analyzed the thermal deformation characteristics. Conclusions can be drawn as follows:(1) The test discovered the influence of deformation parameters on flow stress of β-CEZ titanium alloy, found out the alloy are sensitivity to the deformation temperature and strain rate, showing two softening mechanisms(dynamic recovery and dynamic recrystallization) at the different deformation temperature and strain rate. Discontinuous yielding can be explained in β phase region at higher strain rate, this phenomenon was associated with the sudden generation of new mobile dislocation from grain boundary sources.(2) Established the constitutive model based on Arrhenius equation with parameters Z and artificial neural network, obtained the activation energy. Two constitutive model both have high accuracy.(3) According to the processing map theory, established the processing map by using mathematics and artificial neural network two methods based on dynamic material model. Found out at the high power dissipation rate area occurs the spheroidization of α lamellae( 800~850 /0.01~0.1) and the dynamic recrystallization(900~1000 /0.1). At the flow instability area occurs the adiabatic shear band(800~850 /1~10) and the non-uniform deformation(900~1000 /10). To lay down the thermal deformation technology should be avoid with these area.(4) Based on the material constitutive model established by this study, do FEM with thermal deformation process parameters selected by the processing map. Simulated and analyzed the actual production process and applied the constitutive model and processing map established by this study.