Rearch On High-temperature Plastic Deformation Behavior And Rolling Temperature Field Of TZM

TZM alloy (Titaniun-Zirconium-Molybdenum Alloy) which is a kind of molybdenum-based alloys has been widely applied as a high-temperature alloy in many fields. Its characteristics are high melting point, high strength, high elastic modulus, small expansion coefficient, good electrical and thermal conductivities, good corrosion resistance and good mechanical property under high temperature.The alloy billets used in the test are prepared by powder metallurgy method. The dynamic softening behavior of molybdenum alloys TZM and the influence of deformation processing parameters on deforming resistance are studied by single press test with MMS-300thermo-mechanical simulator. TZM microstructure and second-phase are analysed by XRD、 EPMA and TEM. Temperature difference calculation model of TZM plate during rolling process is established based on the study on calculation method of rolling temperature distribution. The calculation results have valuable references to make TZM plate rolling process.The main work and research results are as follows:(1) The single press deformation method is employed to study thermal deformation dynamic softening behavior of molybdenum alloy TZM,which confirms the parameter of hyperbolic sine model of specific stress, deformation temperature and deformation rate. Dynamic recrystallization activation energy of experiment molybdenum alloy TZM is460.268KJ/mol. the modified Arrhenius formula of TZM is got.ε=0.85688×109·[sinh(0.03486·σ)]2.0023·exp(-460267.91/RT)(2) Deformation temperature and deformation rate are closely related with the hot deformation behavior of TZM. With the rise of deformation temperature and with the decrease of deformation rate, the stress-strain curve changes from dynamic recovery type to dynamic recrystallization type.TZM presents dynamic recrystallization for the first time deformed at1400℃in0.004s-1.(3) A deforming resistance mathematical model in thermal deformation process is established by using the stress-strain curve of molybdenum alloy TZM. (4) Second phases whose sizes are a little bigger are substantially identified as Mo oxides, Ti oxides and Zr oxides,and the amount and type of the second phases in grain are more than that at grain boundary; the second phases below10nm are substantially TiC,Mo2C,ZrC and a small amount of oxide which are disperse distribution.(5) According to the basic principles of heat transfer,modes of heat transfer are analysed during plate rolling process. On above basis, temperature difference calculation models during air colling stage and rolling stage of TZM plate are established and finally temperature field model of TZM plate during rolling process is determined.TZM plate hot rolling process is determined through the temperature field model and thermal simulation results...