The phase transformation activation energy of the Cu61.13Zn33.94A14.93 alloys, which were treated at 4 GPa and 700 ℃ for 15 minutes, was calculated by means of differential scanning calorimetry curves obtained at var...The phase transformation activation energy of the Cu61.13Zn33.94A14.93 alloys, which were treated at 4 GPa and 700 ℃ for 15 minutes, was calculated by means of differential scanning calorimetry curves obtained at various heating and cooling rates. Then, the effects of high-pressure heat treatments on the solid-state phase transformation and the microstructures of Cu61.13Zn33.94A14.93 alloys were investigated. The results show that high-pressure heat treatments can refine the grains and can change the preferred orientation from （111） to （200） of α phase. Compared with the as-cast alloy, the sample with high-pressure heat treatment has finer grains, lower β＇→β and/β→β＇ transformation temperature and activation energy. Furthermore, we found that high cooling rate favours the formation of fine needle-like α phase in the range of 5-20℃/min.展开更多
The temperature,duration,activation energy,and Avrami exponent of the solid phase transformationβ_(1)→α+β_(2) of TC4 titanium alloy treated at 3 GPa in a cooling process are calculated by means of differential sca...The temperature,duration,activation energy,and Avrami exponent of the solid phase transformationβ_(1)→α+β_(2) of TC4 titanium alloy treated at 3 GPa in a cooling process are calculated by means of differential scanning calorimetric curves.Then the effects of high pressure on theβ_(1)→α+β_(2) phase transformation dynamics of TC4 alloy in a cooling process are investigated.The results show that 3 GPa high pressure treatment can increase the activation energy of the TC4 alloy.The beginning time,end time,and duration of theβ_(1)→α+β_(2) phase transition of the 3 GPa high pressure treated TC4 alloy at the cooling rate of 10℃/min are increased by 2.90℃,7.78℃ and-29.28 s respectively.It is known that 3 GPa high pressure treatment has little effect on the phase transition mechanism.展开更多
文摘The phase transformation activation energy of the Cu61.13Zn33.94A14.93 alloys, which were treated at 4 GPa and 700 ℃ for 15 minutes, was calculated by means of differential scanning calorimetry curves obtained at various heating and cooling rates. Then, the effects of high-pressure heat treatments on the solid-state phase transformation and the microstructures of Cu61.13Zn33.94A14.93 alloys were investigated. The results show that high-pressure heat treatments can refine the grains and can change the preferred orientation from （111） to （200） of α phase. Compared with the as-cast alloy, the sample with high-pressure heat treatment has finer grains, lower β＇→β and/β→β＇ transformation temperature and activation energy. Furthermore, we found that high cooling rate favours the formation of fine needle-like α phase in the range of 5-20℃/min.
文摘The temperature,duration,activation energy,and Avrami exponent of the solid phase transformationβ_(1)→α+β_(2) of TC4 titanium alloy treated at 3 GPa in a cooling process are calculated by means of differential scanning calorimetric curves.Then the effects of high pressure on theβ_(1)→α+β_(2) phase transformation dynamics of TC4 alloy in a cooling process are investigated.The results show that 3 GPa high pressure treatment can increase the activation energy of the TC4 alloy.The beginning time,end time,and duration of theβ_(1)→α+β_(2) phase transition of the 3 GPa high pressure treated TC4 alloy at the cooling rate of 10℃/min are increased by 2.90℃,7.78℃ and-29.28 s respectively.It is known that 3 GPa high pressure treatment has little effect on the phase transition mechanism.
