中国物理B ›› 1998, Vol. 7 ›› Issue (6): 451-457.doi: 10.1088/1004-423X/7/6/007

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THE THERMAL DIFFUSIVITIES OF NANOSTRUCTURED NiAl ALLOYS MEASURED BY USING PHOTOACOUSTIC TECHNIQUE

吴柏枚1, 杜英磊2, 秦晓英3, 张立德3   

  1. (1)Department of Physics, University of Science and Technology of China, Hefei 230026, China; (2)Fundamental Physics Center, University of Science and Technology of China, Hefei 230026, China; (3)Institute of Solid State Physics, Academia Sinica, Hefei 230031, China
  • 收稿日期:1997-03-04 修回日期:1998-01-17 出版日期:1998-06-20 发布日期:1998-06-20
  • 基金资助:
    Project supported in part by the Special Research Foundation for Ph. D. Station(No. 020903) and National Laboratory of Modern Acoustics, Nanjing, China.

THE THERMAL DIFFUSIVITIES OF NANOSTRUCTURED NiAl ALLOYS MEASURED BY USING PHOTOACOUSTIC TECHNIQUE

DU YING-LEI (杜英磊)a, WU BAI-MEI (吴柏枚)b, QIN XIAO-YING (秦晓英)c, ZHANG LI-DE (张立德)c   

  1. a Fundamental Physics Center, University of Science and Technology of China, Hefei 230026, China; b Department of Physics, University of Science and Technology of China, Hefei 230026, China; c Institute of Solid State Physics, Academia Sinica, Hefei 230031, China
  • Received:1997-03-04 Revised:1998-01-17 Online:1998-06-20 Published:1998-06-20
  • Supported by:
    Project supported in part by the Special Research Foundation for Ph. D. Station(No. 020903) and National Laboratory of Modern Acoustics, Nanjing, China.

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摘要： The thermal diffusivities of nanostructured NiAl (n-NiAl) alloys wit h different relative densities and the polycrystalline NiAl alloy are measured by using photoacoustic technique in which the signal is detected at the front surface while the rear-surface is excited. It is shown that the values of thermal diffusivity of the nanostructured NiAl alloy are lower than that of the polycry stalline NiAl alloy. The thermal diffusivities of n-NiAl alloys decrease with t he decrease of their relative densities when they are over 70%. When the relativ e density of n-NiAl alloys is lower than 70%, an anomalous increase of thermal diffusivity is observed, which indicates there exists a critical excess volume ΔVc (or critical relative density) in n-NiAl alloys near 70%. Th e results are discussed.

Abstract: The thermal diffusivities of nanostructured NiAl (n-NiAl) alloys wit h different relative densities and the polycrystalline NiAl alloy are measured by using photoacoustic technique in which the signal is detected at the front surface while the rear-surface is excited. It is shown that the values of thermal diffusivity of the nanostructured NiAl alloy are lower than that of the polycry stalline NiAl alloy. The thermal diffusivities of n-NiAl alloys decrease with t he decrease of their relative densities when they are over 70%. When the relativ e density of n-NiAl alloys is lower than 70%, an anomalous increase of thermal diffusivity is observed, which indicates there exists a critical excess volume ΔVc (or critical relative density) in n-NiAl alloys near 70%. Th e results are discussed.

中图分类号:  (Thermal diffusivity)

  • 66.30.Xj
72.15.Eb (Electrical and thermal conduction in crystalline metals and alloys) 61.46.-w (Structure of nanoscale materials)