J Mater Sci Technol ›› 2009, Vol. 25 ›› Issue (04): 475-478.

• Articles • Previous Articles     Next Articles

Thermodynamic Properties of Nanograin Boundary and Thermal Stability of Nanograin Structure

Jun Wei, Xiaoyan Song, Qingchao Han, Lingmei Li   

  1. College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100124, China
  • Received:2008-05-26 Online:2009-07-28 Published:2009-10-10
  • Contact: Xiaoyan Song
  • Supported by:

    the National Natural Science Foundation of China (Nos. 50401001 and 50671001)
    the Program for New Century Excellent Talents in University, China (NCET 2006)
    the Doctorate Foundation of Chinese Education Ministry, China (No. 20070005010)

Abstract:

The thermal features of the nanograin boundary were described by a developed thermodynamic model. Using the nanocrystalline Cu as an example, the pressure, the bulk modulus, and the volume thermal expansion coefficient were calculated to characterize the thermodynamic properties of the grain boundaries on the nanoscale. Based on the parabola-type relationship between the excess free energy and the excess volume of the nanograin boundary, the thermal stability, as well as its evolution characteristics, was analyzed. The experimental results of the temperature-varying grain growth in the nanocrystalline Cu, which exhibited the discontinuous nanograin growth behavior, verified the thermodynamic predictions. In addition, the quantitative relationships correlating the excess volume and the lattice expansion with the nanograin size were discussed.

Key words: Thermodynamic properties, Thermal stability, Nanograin growth, Excess volume