J Mater Sci Technol ›› 2000, Vol. 16 ›› Issue (04): 379-382.

• Research Articles • Previous Articles     Next Articles

Positron lifetime study of the single-phase B2Ni(100-x)Al(x) and Ni50-xCOxAl50 intermetallics

Rongshi CHEN, Jianting GUO, Wenlong ZHOU, Liangyue XIONG   

  1. Department of Superalloys, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China...
  • Received:1999-07-08 Revised:1999-08-11 Online:2000-07-28 Published:2009-10-10
  • Contact: Jianting GUO

Abstract: In order to understand the point defect structure in NiAl Intermetallic compound, the positron lifetime in binary Ni100-xAlx (53 greater than or equal to x greater than or equal to 45) and ternary B2 Ni50-xCoxAl50 (x=0, 5, 10, 15) intermetallic compounds as a function of composition were measured. It is shown that the positron lifetime spectra of these compounds can be consistently expressed by single-component lifetimes. The positron lifetime value in ternary Ni50-xCoxAl50 alloy is independent of Co content and equal to that detected in both stoichiometric and Al-rich NiAl. From an analysis of the present results, it is suggested that the constant lifetime of tau approximate to 180 ps should be ascribed to saturation trapping and annihilation of positron exclusively at Ni vacancy, no evidence for the presence of Al vacancy is available.

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