The relationship among microstructure,mechanical properties and texture of TA32 titanium alloy sheets during hot tensile deformation at 800℃was investigated.In the test,the original sheet exhibited relatively low flo...The relationship among microstructure,mechanical properties and texture of TA32 titanium alloy sheets during hot tensile deformation at 800℃was investigated.In the test,the original sheet exhibited relatively low flow stress and sound plasticity,and increasing the heat treatment temperature resulted in an increased ultimate tensile strength(UTS)and a decreased elongation(EL).The deformation mechanism of TA32 alloy was dominated by high angle grain boundaries sliding and coordinated by dislocation motion.The coarsening of grains and the annihilation of dislocations in heat-treated specimens weakened the deformation ability of material,which led to the increase in flow stress.Based on the high-temperature creep equation,the quantitative relationship between microstructure and flow stress was established.The grain size exponent andαphase strength constant of TA32 alloy were calculated to be 1.57 and 549.58 MPa,respectively.The flow stress was accurately predicted by combining with the corresponding phase volume fraction and grain size.Besides,the deformation behavior of TA32 alloy was also dependent on the orientation of predominantαphase,and the main slip mode was the activation of prismaticslip system.The decrease of near prism-oriented texture in heat-treated specimens resulted in the enhancement of strength of the material.展开更多
The hot flow behaviors,microstructure evolution and fractographs were studied to optimize the hot forming process of the TA32 titanium alloy thin-walled part.A set of microstructure-based constitutive equations were d...The hot flow behaviors,microstructure evolution and fractographs were studied to optimize the hot forming process of the TA32 titanium alloy thin-walled part.A set of microstructure-based constitutive equations were developed based on the experimental data,which described the relationships among the hot flow stresses and the evolution of phase volume fraction,dislocation density,grain size and damage.The constitutive model was imported into ABAQUS 6.14 to simulate the hot forming process for a typical thin-walled part.The effective strain,dislocation density and damage distribution as well as forming defects of formed parts under different process parameters were predicted.A qualified part without wrinkling and fracture defects was produced at a loading speed of 5 mm/s at 800℃ by the modified blank shape,where the maximum damage value was only 18.3%.The accuracy of constitutive model and finite element(FE)simulation was verified by the microhardness tests,which indicates that the FE model based on physical internal-state variables can well optimize the hot forming process of TA32 titanium alloy complex parts.展开更多
基金Project(51805256)supported by the National Natural Science Foundation of China。
文摘The relationship among microstructure,mechanical properties and texture of TA32 titanium alloy sheets during hot tensile deformation at 800℃was investigated.In the test,the original sheet exhibited relatively low flow stress and sound plasticity,and increasing the heat treatment temperature resulted in an increased ultimate tensile strength(UTS)and a decreased elongation(EL).The deformation mechanism of TA32 alloy was dominated by high angle grain boundaries sliding and coordinated by dislocation motion.The coarsening of grains and the annihilation of dislocations in heat-treated specimens weakened the deformation ability of material,which led to the increase in flow stress.Based on the high-temperature creep equation,the quantitative relationship between microstructure and flow stress was established.The grain size exponent andαphase strength constant of TA32 alloy were calculated to be 1.57 and 549.58 MPa,respectively.The flow stress was accurately predicted by combining with the corresponding phase volume fraction and grain size.Besides,the deformation behavior of TA32 alloy was also dependent on the orientation of predominantαphase,and the main slip mode was the activation of prismaticslip system.The decrease of near prism-oriented texture in heat-treated specimens resulted in the enhancement of strength of the material.
基金financially supported by the National Natural Science Foundation of China(No.51805256)。
文摘The hot flow behaviors,microstructure evolution and fractographs were studied to optimize the hot forming process of the TA32 titanium alloy thin-walled part.A set of microstructure-based constitutive equations were developed based on the experimental data,which described the relationships among the hot flow stresses and the evolution of phase volume fraction,dislocation density,grain size and damage.The constitutive model was imported into ABAQUS 6.14 to simulate the hot forming process for a typical thin-walled part.The effective strain,dislocation density and damage distribution as well as forming defects of formed parts under different process parameters were predicted.A qualified part without wrinkling and fracture defects was produced at a loading speed of 5 mm/s at 800℃ by the modified blank shape,where the maximum damage value was only 18.3%.The accuracy of constitutive model and finite element(FE)simulation was verified by the microhardness tests,which indicates that the FE model based on physical internal-state variables can well optimize the hot forming process of TA32 titanium alloy complex parts.
