In this paper,the springback of TC4 titanium alloy under hot stamping condition was studied by means of experiment and numerical analysis.Firstly,an analytical model was established to predict the V-shaped springback ...In this paper,the springback of TC4 titanium alloy under hot stamping condition was studied by means of experiment and numerical analysis.Firstly,an analytical model was established to predict the V-shaped springback angleΔαunder the stretch-bending conditions.The model took into account of blank holder force,friction,property of the material,thickness of the sheet and the neutral layer shift.Then,the influence of several process parameters on springback was studied by experiment and finite element simulation using a V-shaped stamping tool.In the hot stamping tests,the titanium alloy sheet fractured seriously at room temperature.The titanium alloy has good formability when the initial temperature of the sheet is 750–900°C.However,the springback angle of formed parts is large and decreases with increasing temperature.The springback angleΔαdecreased by 50%from 0.5°to 0.25°,and the angleΔβdecreased by 46.7%from 1.5°to 0.8°when the initial temperature of sheet increased from 750°C to 900°C.The springback angle of titanium alloy sheet increases gradually with the increase of the punch radius,because of the increase of elastic recovery,the complex distribution of stress,the length of forming region and the decreasing degree of stress.Compared with the simulation results,the analytical model can better predict the springback angleΔα.展开更多
In the present work, a novel hybrid composite composed of Ti-aluminide multi-layered part and continuous-SiCf-reinforced Ti-matrix part using a vacuum hot pressing/hot isostatic pressure(VHP/HIP) sintering process was...In the present work, a novel hybrid composite composed of Ti-aluminide multi-layered part and continuous-SiCf-reinforced Ti-matrix part using a vacuum hot pressing/hot isostatic pressure(VHP/HIP) sintering process was synthesized. Then,the damage tolerance behavior of this hybrid composite was studied by tensile tests and in situ scanning electron microscopy(SEM) three-point bending tests. The results indicate that the mechanical properties and crack propagation of the hybrid composite are strongly influenced by the extrinsic toughness mechanism. In detail, the crack deflection of multi-layered composite and strengthening effect of SiCf-reinforced matrix composite are observed in the hybrid composite.Owing to the strengthening effect of continuous-SiCf-reinforced Ti-matrix part, the tensile strength of hybrid composite is much higher than that of neat Ti-aluminide multi-layered composite. Furthermore, it is found that the optimal damage tolerance ability is optimized when the notch position is located at the Ti-aluminide multi-layered part due to the crack deflection of multi-layered structure.展开更多
基金Projects(U1564202,51705018)supported by the National Natural Science Foundation of ChinaProject supported by the Beijing Laboratory of Modern Transportation Metal Materials and Processing Technology and the Beijing Key Laboratory of Metal Forming Lightweight,China。
文摘In this paper,the springback of TC4 titanium alloy under hot stamping condition was studied by means of experiment and numerical analysis.Firstly,an analytical model was established to predict the V-shaped springback angleΔαunder the stretch-bending conditions.The model took into account of blank holder force,friction,property of the material,thickness of the sheet and the neutral layer shift.Then,the influence of several process parameters on springback was studied by experiment and finite element simulation using a V-shaped stamping tool.In the hot stamping tests,the titanium alloy sheet fractured seriously at room temperature.The titanium alloy has good formability when the initial temperature of the sheet is 750–900°C.However,the springback angle of formed parts is large and decreases with increasing temperature.The springback angleΔαdecreased by 50%from 0.5°to 0.25°,and the angleΔβdecreased by 46.7%from 1.5°to 0.8°when the initial temperature of sheet increased from 750°C to 900°C.The springback angle of titanium alloy sheet increases gradually with the increase of the punch radius,because of the increase of elastic recovery,the complex distribution of stress,the length of forming region and the decreasing degree of stress.Compared with the simulation results,the analytical model can better predict the springback angleΔα.
基金financially supported by the National Science and Technology Major Project (No.2012ZX04012011)
文摘In the present work, a novel hybrid composite composed of Ti-aluminide multi-layered part and continuous-SiCf-reinforced Ti-matrix part using a vacuum hot pressing/hot isostatic pressure(VHP/HIP) sintering process was synthesized. Then,the damage tolerance behavior of this hybrid composite was studied by tensile tests and in situ scanning electron microscopy(SEM) three-point bending tests. The results indicate that the mechanical properties and crack propagation of the hybrid composite are strongly influenced by the extrinsic toughness mechanism. In detail, the crack deflection of multi-layered composite and strengthening effect of SiCf-reinforced matrix composite are observed in the hybrid composite.Owing to the strengthening effect of continuous-SiCf-reinforced Ti-matrix part, the tensile strength of hybrid composite is much higher than that of neat Ti-aluminide multi-layered composite. Furthermore, it is found that the optimal damage tolerance ability is optimized when the notch position is located at the Ti-aluminide multi-layered part due to the crack deflection of multi-layered structure.
