Thermal Deformation Behavior And Process Parameter Optimization Of Ti60 Alloy

Ti60 alloy is widely used in key parts of aero-engine because of excellent properties such as thermal stability,creep resistance and oxidation resistance.In addition,continuous SiC fiber-reinforced Ti60 matrix composites(SiC_f/Ti60)with high specific strength,high specific stiffness and good high temperature resistance have become one of the important candidate structural materials for ultra-high speed space vehicles and the next generation of advanced aircraft engines.In this paper,the application background of SiC_f/Ti60 composite components is hot pressure or hot isostatic compaction,and the Ti60 alloy is taken as the research object.The isothermal constant strain rate compression test is conducted on the alloy samples under the conditions of deformation temperature 600?950?,strain rate 0.001?10s^-1and true strain 0.51,to obtain the flow stress-strain data of the alloy.The flow stress behavior of Ti60 alloy was analyzed,the softening mechanism was studied,and the constitutive relationship was established.The results of this study can provide a theoretical basis for the preparation of thermal and thermal isostatic pressure processes of SiC_f/Ti60 composite components and the finite element simulation of thermal and thermal isostatic pressure.The main research results are as follows:Ti60 alloy flow stress decreased with the increase of deformation temperature and strain rate decreases,and at(800?950?)of(0.001?0.1s^-1)range,flow stress-strain curve is roughly the steady-state flow characteristic,but at(800?950?)of(1?10 s^-1)and all the strain rate range(0.001?10 s^-1)of(600?750?),flow stress-strain curve is roughly flow softening characteristics.Considering the characteristic of no inflection point of the working hardening rate curve,the difference of the deformation activation energy between the flow steady state type and the flow softening type,and the typical dynamic recovery structure of the deformation microstructure,the dynamic recovery mechanism of Ti60 alloy was determined.The constitutive model of Ti60 alloy was established based on Arrhenuis equation,multiple linear regression equation and artificial neural network.Among them,the constitutive model based on the hyperbolic sine function Arrhenuis equation has a low computational accuracy,which is not suitable for directly characterizing the high temperature plastic flow behavior of Ti60 alloy.However,the constitutive model based on multiple linear regression equation and artificial neural network(ANN)can well meet the needs of engineering applications,and the constitutive model based on ANN has better accuracy,which can more accurately describe and predict the flow stress behavior of Ti60 alloy.Considering the influence of deformation parameters on deformation temperature sensitive index,strain hardening sensitive index and processing map,the optimum machining parameter range of Ti60 alloy was optimized.from the perspective of strain rate-sensitive index m and strain hardening index n of Ti60 alloy,the appropriate thermal pressure or thermal isostatic pressure parameters of SiC_f/Ti60 composite components are temperature 800?950?and strain rate 0.001?0.1s^-1.however,From the perspective of processing map,the preferred thermal pressure or thermal isostatic pressure parameters of SiCf/Ti60 composite components are temperature 725?875?,strain rate?0.003s^-1,or temperature 875?938?,strain rate?0.04s^-1.Combined with these results,it can be concluded that the optimal thermal pressure or thermal isostatic pressure parameters of SiC_f/Ti60 composite components are 800?875?,strain rate0.001?0.003s^-1,or 875?938?,strain rate 0.001?0.04s^-1.