The effect of holding time of double annealing process on the microstructure and mechanical properties of Ti-5Al-5Mo-5V1Cr-1Fe(Ti55511)alloy was investigated.Results reveal that the shape and size of the primaryα(α_...The effect of holding time of double annealing process on the microstructure and mechanical properties of Ti-5Al-5Mo-5V1Cr-1Fe(Ti55511)alloy was investigated.Results reveal that the shape and size of the primaryα(α_(p))phase are predominantly influenced by the holding time at the first stage.With the prolongation of holding time,the long strip of α_(p) is transformed into a short rod due to the terminal migration mechanism,leading to the broadening growth,and the growth of α_(p) slows down when the holding time is over 2 h.The volume fraction of α_(p) is mainly affected by the holding time of the second stage:with the prolongation of holding time,the volume fraction of α_(p) is increased,which is accompanied by the precipitation of the secondaryα(α_(s)).The mechanical properties of Ti55511 alloy are influenced by bothα_(p) andαs.Tensile results indicate that the optimal holding time of double annealing is 1-4 h for the first stage and 0.5-2 h for the second stage.展开更多
The hot deformation behavior of as-extruded Ti-6554 alloy was investigated through isothermal compression at 700–950°C and 0.001–1 s^(−1).The temperature rise under different deformation conditions was calculat...The hot deformation behavior of as-extruded Ti-6554 alloy was investigated through isothermal compression at 700–950°C and 0.001–1 s^(−1).The temperature rise under different deformation conditions was calculated,and the curve was corrected.The strain compensation constitutive model of as-extruded Ti-6554 alloy based on temperature rise correction was established.The microstructure evolution under different conditions was analyzed,and the dynamic recrystallization(DRX)mechanism was revealed.The results show that the flow stress decreases with the increase in strain rate and the decrease in deformation temperature.The deformation temperature rise gradually increases with the increase in strain rate and the decrease in deformation temperature.At 700°C/1 s^(−1),the temperature rise reaches 100°C.The corrected curve value is higher than the measured value,and the strain compensation constitutive model has high prediction accuracy.The precipitation of theαphase occurs during deformation in the twophase region,which promotes DRX process of theβphase.At low strain rate,the volume fraction of dynamic recrystallization increases with the increase in deformation temperature.DRX mechanism includes continuous DRX and discontinuous DRX.展开更多
文摘The effect of holding time of double annealing process on the microstructure and mechanical properties of Ti-5Al-5Mo-5V1Cr-1Fe(Ti55511)alloy was investigated.Results reveal that the shape and size of the primaryα(α_(p))phase are predominantly influenced by the holding time at the first stage.With the prolongation of holding time,the long strip of α_(p) is transformed into a short rod due to the terminal migration mechanism,leading to the broadening growth,and the growth of α_(p) slows down when the holding time is over 2 h.The volume fraction of α_(p) is mainly affected by the holding time of the second stage:with the prolongation of holding time,the volume fraction of α_(p) is increased,which is accompanied by the precipitation of the secondaryα(α_(s)).The mechanical properties of Ti55511 alloy are influenced by bothα_(p) andαs.Tensile results indicate that the optimal holding time of double annealing is 1-4 h for the first stage and 0.5-2 h for the second stage.
基金National Key R&D Program of China(2022YFB3706901)National Natural Science Foundation of China(52274382)Key Research and Development Program of Hubei Province(2022BAA024)。
文摘The hot deformation behavior of as-extruded Ti-6554 alloy was investigated through isothermal compression at 700–950°C and 0.001–1 s^(−1).The temperature rise under different deformation conditions was calculated,and the curve was corrected.The strain compensation constitutive model of as-extruded Ti-6554 alloy based on temperature rise correction was established.The microstructure evolution under different conditions was analyzed,and the dynamic recrystallization(DRX)mechanism was revealed.The results show that the flow stress decreases with the increase in strain rate and the decrease in deformation temperature.The deformation temperature rise gradually increases with the increase in strain rate and the decrease in deformation temperature.At 700°C/1 s^(−1),the temperature rise reaches 100°C.The corrected curve value is higher than the measured value,and the strain compensation constitutive model has high prediction accuracy.The precipitation of theαphase occurs during deformation in the twophase region,which promotes DRX process of theβphase.At low strain rate,the volume fraction of dynamic recrystallization increases with the increase in deformation temperature.DRX mechanism includes continuous DRX and discontinuous DRX.
文摘在Gleeble-3800热模拟试验机上对15-5PH钢进行高温热压缩试验,研究该材料在变形温度850-1180℃、应变速率0.001-10 s^-1、真应变量约为0.9条件下的热变形行为。采用双曲正弦模型建立了该材料的高温变形本构关系,依据动态材料模型建立并分析了其热加工图。结果表明：在热压缩过程中,峰值应力随变形温度的升高而减小,随应变速率的升高而增大,当变形速率较低时,材料在变形温度范围内均发生了动态再结晶。15-5PH钢的热变形激活能为228.41 k J/mol。从热加工图中获得了该材料最佳热加工参数范围是：变形温度1000-1150℃、应变速率0.001-0.1 s^-1。
