Program

P.50 -- Poster, NCTP-41

Date: Wednesday, 3 August 2016

Time: 08h30 - 10h00

Thermodynamic property of interstitial alloy FeSi with vacancy and BCC structure: Dependence on temperature, concentration of interstitial atoms and concentration of equilibrium vacancies

Nguyen Quang Hoc (1), Nguyen Thi Hoa (2), Luong Xuan Phuong (1), Pham Thi Minh Hanh (3) and Le Hong Viet (4)

(1)Hanoi National University of Education, 136 Xuan Thuy, Cau Giay District, Hanoi (2)University of Transport and Communications, 3 Cau Giay, Dong Da district, Hanoi, (3) Hanoi Pedagogic University No.2, Xuan Hoa, Phuc Yen Town, Vinh Phuc Province, (4) Tran Quoc Tuan University, Co Dong, Son Tay Town, Hanoi

The analytic expressions for the concentration of equilibrium vacancies and the thermodynamic quantities such as the mean nearest neighbor distance, the free energy, the isothermal and adiabatic compressibilities, the isothermal and adiabatic elastic modulus, the thermal expansion coefficient, the heat capacities at constant volume and at constant pressure, the entropy of binary interstitial alloy with defect and with body-centered cubic (BCC) structure with the concentration of interstitial atoms is small (below 5\%) are derived by the statistical moment method. The obtained expressions of these quantities depend on temperature, concentration of interstitial atoms and concentration of equilibrium vacancies. The theoretical results are applied to interstitial alloy FeSi in the interval of temperature from 600 to 1000K and in the interval of interstitial atom concentration from 0 to 5\%. In the case when the concentration of interstitial atoms Si is equal to zero, we obtain the thermodynamic quantities of main metal Fe with defect. Our calculated results for the thermal expansion coefficient and the heat capacity under constant pressure of main metal Fe are in good agreement with experiments. Our results show that the concentration of equilibrium vacancies affect thermodynamic property of interstitial alloy in high temperatures.

Presenter: Nguyễn Thị Hòa