The precipitation behavior of V（C, N） in steels microalloyed with vanadium was researched using a thermal simulator during single-pass deformation at 800-750 ℃. The V（C, N） precipitates and its nucleation effect ...The precipitation behavior of V（C, N） in steels microalloyed with vanadium was researched using a thermal simulator during single-pass deformation at 800-750 ℃. The V（C, N） precipitates and its nucleation effect on ferrite were investigated by TEM and EDS. The experimental results show that there are two remarkable heterogeneous nucleation effects of V（C, N） particles precipitated before γ →/ α phase change： primary reason is that high coherency between V（C, N） and ferrite promotes V（C, N） to become a nucleating center of intragranular ferrite; secondary reason is that the coarsening of V（C, N） causes locally solute-poor region in austenite, thus expedites the nucleation of intragranular ferrites further. Furthermore, the relationship between the size and shape of V（C, N） was studied, and identification method was provided for distinguishing interphase precipitation and general precipitation to avoid erroneous judgment and misguide.展开更多
The precipitation of Ti(V)N(C)in high-carbon steel PD_3 during thermomechanicol treatment at austenitic temperatures after deformation has been observed.The average size of Ti(V)N(C)particles may reduce with the incre...The precipitation of Ti(V)N(C)in high-carbon steel PD_3 during thermomechanicol treatment at austenitic temperatures after deformation has been observed.The average size of Ti(V)N(C)particles may reduce with the increase of strain and the decrease of thermomechanical treatment temperature,and vise versa.The growth of Ti(V)N(C)particles at 920°C is found to be controlled by the interface reaction between precipitated particles and matrix.展开更多
We report on the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Pd/Ti/n-InP Schottky barrier diodes (SBDs) in the temperature range 160-400 K in steps of 40 K. The barrier heights and ideal...We report on the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Pd/Ti/n-InP Schottky barrier diodes (SBDs) in the temperature range 160-400 K in steps of 40 K. The barrier heights and ideality factors of Schottky contact are found in the range 0.35 eV (I-V), 0.73 eV (C-V) at 160 K and 0.63 eV (I-V), 0.61 eV (C-V) at 400 K, respectively. It is observed that the zero-bias barrier height decreases and ideality factor n increase with a decrease in temperature, this behaviour is attributed to barrier inhomogeneities by assuming Gaussian distribution at the interface. The calculated value of series resistance (Rs) from the forward I-V characteristics is decreased with an increase in temperature. The homogeneous barrier height value of approximately 0.71 eV for the Pd/Ti Schottky diode has been obtained from the linear relationship between the temperature-dependent experimentally effective barrier heights and ideality factors. The zero-bias barrier height ( ) versus 1/2kT plot has been drawn to obtain evidence of a Gaussian distribution of the barrier heights and values of = 0.80 eV and = 114 mV for the mean barrier height and standard deviation have been obtained from the plot, respectively. The modified Richardson ln(I0/T2)- ( ) versus 1000/T plot has a good linearity over the investigated temperature range and gives the mean barrier height ( ) and Richardson constant (A*) values as 0.796 eV and 6.16 Acm-2K-2 respectively. The discrepancy between Schottky barrier heights obtained from I-V and C-V measurements is also interpreted.展开更多
基金Funded by the National Natural Science Foundation of China (50775102)the Universities Natural Science Fund Key Project of Jiangsu Province (04KJA430021)
文摘The precipitation behavior of V（C, N） in steels microalloyed with vanadium was researched using a thermal simulator during single-pass deformation at 800-750 ℃. The V（C, N） precipitates and its nucleation effect on ferrite were investigated by TEM and EDS. The experimental results show that there are two remarkable heterogeneous nucleation effects of V（C, N） particles precipitated before γ →/ α phase change： primary reason is that high coherency between V（C, N） and ferrite promotes V（C, N） to become a nucleating center of intragranular ferrite; secondary reason is that the coarsening of V（C, N） causes locally solute-poor region in austenite, thus expedites the nucleation of intragranular ferrites further. Furthermore, the relationship between the size and shape of V（C, N） was studied, and identification method was provided for distinguishing interphase precipitation and general precipitation to avoid erroneous judgment and misguide.
文摘The precipitation of Ti(V)N(C)in high-carbon steel PD_3 during thermomechanicol treatment at austenitic temperatures after deformation has been observed.The average size of Ti(V)N(C)particles may reduce with the increase of strain and the decrease of thermomechanical treatment temperature,and vise versa.The growth of Ti(V)N(C)particles at 920°C is found to be controlled by the interface reaction between precipitated particles and matrix.
文摘We report on the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Pd/Ti/n-InP Schottky barrier diodes (SBDs) in the temperature range 160-400 K in steps of 40 K. The barrier heights and ideality factors of Schottky contact are found in the range 0.35 eV (I-V), 0.73 eV (C-V) at 160 K and 0.63 eV (I-V), 0.61 eV (C-V) at 400 K, respectively. It is observed that the zero-bias barrier height decreases and ideality factor n increase with a decrease in temperature, this behaviour is attributed to barrier inhomogeneities by assuming Gaussian distribution at the interface. The calculated value of series resistance (Rs) from the forward I-V characteristics is decreased with an increase in temperature. The homogeneous barrier height value of approximately 0.71 eV for the Pd/Ti Schottky diode has been obtained from the linear relationship between the temperature-dependent experimentally effective barrier heights and ideality factors. The zero-bias barrier height ( ) versus 1/2kT plot has been drawn to obtain evidence of a Gaussian distribution of the barrier heights and values of = 0.80 eV and = 114 mV for the mean barrier height and standard deviation have been obtained from the plot, respectively. The modified Richardson ln(I0/T2)- ( ) versus 1000/T plot has a good linearity over the investigated temperature range and gives the mean barrier height ( ) and Richardson constant (A*) values as 0.796 eV and 6.16 Acm-2K-2 respectively. The discrepancy between Schottky barrier heights obtained from I-V and C-V measurements is also interpreted.
