Dang Thi Minh Hue, Coman Gelu, Nguyen Quang Hoc, Nguyen Trong Dung
Faculty of Electrical and Electronics Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Viet Nam.
"Dunarea de Jos" University of Galati, Romania.
Heliyon. 2020 Nov 19;6(11):e05548. doi: 10.1016/j.heliyon.2020.e05548. eCollection 2020 Nov.
The present article is aimed to investigate influence of the heating rate, temperature (T), pressure (P) on the structure and phase transition of amorphous Ni material with heating rate 2 × 10, 2 × 10 and 2 × 10 K/s at T = 300 K; T = 300, 400, 500, 600, 700, 800, 900 and 1000 K at heating rate 2 × 10 K/s; T = 300, 621 and 900 K at P = 1, 2, 3, 4 and 5 GPa by molecular dynamics simulation method with Sutton-Chen embedded potential and periodic boundary conditions. The structure of amorphous Ni material determined through the radial distribution function, the total energy, the size and the average coordination number. The phase transition and the glass transition temperature determined through the relationship between the total energy and temperature. The result shows that when the heating rate increases, the first peak's position for the radial distribution function is 2.45 Å and a constant, the first peak's height, the total energy and the size increase, the average coordination number decreases from 13 to 12. When temperature increases from 300 to 1000 K at P = 0 GPa, the position decreases from 2.45 Å to 2.40 Å, the average coordination number is 13 and a constant, glass transition temperature is 631 K, the total energy increases, the size increases and happens the phase transition from the amorphous state to the liquid state. When pressure increases from 0 GPa to 5 GPa at T = 300, 621 and 900 K, the position decreases, the height increases, the total energy increases, the size decreases, the average coordination number decreases from 13 to 12, that shows with amorphous Ni material when increasing heating rate, T, P lead to structural change, phase transition of materials is significant.
本文旨在通过采用Sutton-Chen嵌入势和周期性边界条件的分子动力学模拟方法，研究加热速率、温度（T）、压力（P）对非晶态Ni材料结构和相变的影响，加热速率为2×10、2×10和2×10 K/s，温度T = 300 K；加热速率为2×10 K/s时，温度T = 300、400、500、600、700、800、900和1000 K；压力P = 1、2、3、4和5 GPa时，温度T = 300、621和900 K。通过径向分布函数、总能量、尺寸和平均配位数确定非晶态Ni材料的结构。通过总能量与温度的关系确定相变和玻璃化转变温度。结果表明，当加热速率增加时，径向分布函数的第一个峰位置为2.45 Å且保持不变，第一个峰的高度、总能量和尺寸增加，平均配位数从13降至12。在P = 0 GPa时，当温度从300 K升高到1000 K时，位置从2.45 Å降至2.40 Å，平均配位数为13且保持不变，玻璃化转变温度为631 K，总能量增加，尺寸增加，发生从非晶态到液态的相变。在T = 300、621和900 K时，当压力从0 GPa增加到5 GPa时，位置降低，高度增加，总能量增加，尺寸减小，平均配位数从13降至12，这表明对于非晶态Ni材料，加热速率、T、P的增加会导致材料结构变化，材料的相变显著。
