The ω-phase transformation and β-phase stability in Ti-
xNb (28≤
x≤40 at%) single crystals were investigated using electrical resistivity measurements, transmission electron microscopy (TEM) observations, and specific heat measurements. The crystal for
x=28 exhibits distinct anomalous negative temperature dependence of the resistivity coefficient and thermal hysteresis accompanied by the presence of the athermal ω-phase and β-phase lattice modulation. Although the crystal for
x=30 appears in the β-phase lattice modulation, it does not exhibit a clear negative temperature dependence of the resistivity coefficient or the athermal ω-phase. The crystal of
x=30 also shows a relatively high absolute value of resistivity at 15 K among the crystals for 28≤
x≤40 and a low Debye temperature in a normal conductive state. The crystal for
x=30 that shows the lattice modulation, high resistivity, and low β-phase Debye temperature corresponds to the low stability of the β-phase. Moreover, the stability strongly depends on the Nb content in the binary Ti-Nb crystal.
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