Iron content and temperature dependences of diffuse scattering in Ti-(50-x)Ni-xFe (6 ≤ x ≤ 10) alloys.

Diffuse scatterings appearing in electron diffraction patterns of Ti-(50 - x)Ni-xFe (x = 6, 7, 8, 10, in at.%) alloys were investigated. In the alloys, martensitic (R-phase) transformation is suppressed down to 4.2 K, but the electrical resistivity exhibits a local minimum at Tmin (210 K, 195 K, 180 K and 140 K for x = 6, 7, 8, 10, respectively). The following results were obtained for all the alloys. Diffuse scattering appears below Tmin and its intensity maximum is located at an incommensurate position of g + 〈ζζ0〉*, where g is a reciprocal lattice vector of the B2-phase. The value ζ at Tmin is significantly smaller than 1/3 and increases with decreasing temperature; it decreases with increasing Fe content. The value of ζ at Tmin agrees with the length of nesting vector obtained by a band calculation, suggesting that the diffuse scattering is caused by the nesting effect of the Fermi surface in the B2-type structure. [ABSTRACT FROM AUTHOR]