Browsing by Author "Lu, L"

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Electronic transport properties of alpha-TiAl alloys
(2005-10-10)
Zhang, DL
;
Liu, SM
;
Jing, XN
;
Luo, JL
;
Zhang, XG
The electrical resistivity, thermal conductivity, and thermopower of alpha-TiAl alloy samples with A1 content from 0 at.% to 10 at.% are measured from room temperature down to liquid helium temperature. It is found that with the increase in A1 content the single phonon scattering contribution to the resistivity remains nearly constant, but the multiphonon scattering contribution monotonously increases. This provides an alternative explanation of resistivity saturation to the shunt-resistor model. The Wiedemann-Ranz law holds for the whole temperature range, allowing the separation of the electron and phonon contributions to the thermal conductivity. The data from samples with different doping levels enable us to separate the band and the scattering terms in the thermopower.
Superconductivity of alpha-TiAl alloys
(2000-11-01)
Liu, SM
;
Jing, XN
;
Lu, L
;
Li, SL
;
Lin, JJ
The superconducting transition temperature Tc of alpha TiAl alloys has been measured up to 10 atomic percentage of Al. T-c monotonously increases with a tendency to saturation for high Al content.
Upper critical field of Ti and alpha-TiAl alloys: Evidence of an intrinsic type-II superconductivity in pure Ti
(2000-10-01)
Liu, SM
;
Zhang, DL
;
Jing, XN
;
Lu, L
;
Li, SL
The upper critical field H-c2 of alpha-Ti1-xAlx(0 less than or equal to x less than or equal to 0.1) alloys has been investigated in detail. The behaviors can well be described by the theory of type-II superconductors. The electronic specific heat deduced from the superconducting properties is in excellent agreement with previous calorimetric measurements. However, the Fermi velocity obtained here is substantially lower than predicted by band calculation. The present work gives clear evidence that pure Ti is an intrinsic type-II superconducting element due to its very low renormalized Fermi velocity.