Acta Phys. -Chim. Sin. ›› 2002, Vol. 18 ›› Issue (06): 508-512.doi: 10.3866/PKU.WHXB20020607

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Microstructure of Liquid CuAlNi Shape Memory Alloy

Pan Xue-Min;Bian Xiu-Fang;Wang Li   

  1. Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061
  • Received:2001-10-19 Revised:2001-12-20 Published:2002-06-15
  • Contact: Pan Xue-Min E-mail:pxm823@sdu.edu.cn

Abstract: Molten CuAlNi alloys have been investigated by X-ray diffractometer. Distinct pre-peaks have been found in the structure factors. For the liquid alloy Cu75Al25,the intensity of pre-peak decreases with increasing temperature but exists clearly up to temperature of 1300 ℃.This behaviour indicates the existence of medium-range order clusters up to nearly 250 ℃ above liquids temperature. The amount and size of atomic clusters increase as the concentration of Ni increases. The addition of Ni can improve the interaction between atoms, so it is favorable to the ability of medium-range order formation. According to the characteristics of the pre-peak, the atomic model of liquid CuAlNi is constructed, namely,the structure of liquid CuAlNi is a combination of clusters consisting of octahedrons with shared vertexes and other atoms with random dense atom distribution.

Key words: CuAlNi alloy, Liquid structure, Pre-peak, X-ray diffraction