摘要
The addition of high Ti（>0.1%） in microalloyed bainitic high strength steel was designed, and the precipitation morphology of steels with different Ti, Nb, and V contents was studied by utilizing transmission electron microscopy（TEM）. Based on the classical nucleation-crystal growth theory and the Johnson-Mehl-Avrami equation, the precipitation thermodynamic and kinetic model of second phase particles in austenite was established in the form of（Nbx,Vy,Tiz）C, and the complex precipitation mechanism of second phase particles was emphatically studied. The experimental results show that the complex precipitation particles could be divided into two categories: the coarser particles with about 100 nm grain size and the independent complex precipitation particles in the form of（Nb,V,Ti）C with 35-50 nm grain size. The latter has a better precipitation strengthening effect, and the calculated PTT curve shows a typical "C" shape. When the deformed storage energy is 3 820 J?mol-1, the fastest precipitation temperature of calculated PTT curve is 925 °C, and the calculated result is essentially consistent with experimental values. The increase of Ti content increased the nose point temperature and expanded the range of fastest precipitation temperature.
The addition of high Ti(>0.1%) in microalloyed bainitic high strength steel was designed, and the precipitation morphology of steels with different Ti, Nb, and V contents was studied by utilizing transmission electron microscopy(TEM). Based on the classical nucleation-crystal growth theory and the Johnson-Mehl-Avrami equation, the precipitation thermodynamic and kinetic model of second phase particles in austenite was established in the form of(Nbx,Vy,Tiz)C, and the complex precipitation mechanism of second phase particles was emphatically studied. The experimental results show that the complex precipitation particles could be divided into two categories: the coarser particles with about 100 nm grain size and the independent complex precipitation particles in the form of(Nb,V,Ti)C with 35-50 nm grain size. The latter has a better precipitation strengthening effect, and the calculated PTT curve shows a typical "C" shape. When the deformed storage energy is 3 820 J·mol^-1, the fastest precipitation temperature of calculated PTT curve is 925℃, and the calculated result is essentially consistent with experimental values. The increase of Ti content increased the nose point temperature and expanded the range of fastest precipitation temperature.
作者
PANG Qihang
GUO Jing
LI Weijuan
TANG Di
ZHAO Zhengzhi
QI Huan
WANG Jiaji
庞启航;郭菁;LI Weijuan;TANG Di;ZHAO Zhengzhi;QI Huan;WANG Jiaji(School of Materials and Metallurgy,University of Science and Technology Liaoning,Anshan 114051,China;State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan 114009,China;Engineering Research Institute,University of Science and Technology Beijing,Beijing 100083,China)
基金
Funded by the National Natural Science Foundation of China(No.U1860112)
the State Key Laboratory of Marine Equipment made of Metal Material and Application(No.SKLMEAUSTL-201708 and No.SKLMEA-USTL-201703)
the Key Project of Liaoning Education Department(No.2019FWDF03)
the National Natural Science Foundation of USTL(No.2017QN11)
