Electronic and atomic-size effects on the omega phase formation in transition-metal based B.C.C. alloys

Microstructural evolution and ductility improvement of a Ti–30Nb alloy with Pd addition

“…1). This is also confirmed by comparing the atomic sizes (Ti, 0.146 nm; Nb, 0.141 nm; Pd, 0.138 nm; respectively [27]): it is reported that the atoms that are smaller in atomic size than the parent atoms can stabilize the -phase formation via enhanced shear in the alloy [28]. Also, the ␤-Ti-phase possesses high ductility and low elastic modulus, but lower strength [3].…”

Phase selection in non-equilibrium processed TM–Al intermetallic alloys

“…The discovery of various ordered structures in a precursor B2 phase (ordered ␤) in some TiAl based alloys, which contain large quantities of Al [12][13][14] is not consistent with previous understanding of the effect of the ␣-Ti stabilising element Al [15]. The phase has been observed in the Ti-Al-TM (TM = Cr, Nb, V) [12,16,17], TM-Al (TM = Cr, Nb, Mo, Mn, Ni) [18], Ti-TM (TM = V, Cr, Fe, Mn, Nb, Mo, Zr) [15,[19][20][21][22][23][24][25], Zr-Nb [22,26], Hf-Zr [27] and Ni-Al [28] systems.…”

“…4A that the |∆|-e/a data of Ti-Mn deviate remarkably from other Ti-TM alloys. For the Zr-Ti alloys containing 25-50 at.% Ti, the |∆| values increase with increasing Ti content [25]. This is strong evidence that the e/a ratio alone cannot explain the stability of the phase, as the e/a value for Zr-Ti alloys is constant (e/a = 4).…”

“…4 (the low dashed lines) define |∆| = 0.04 (or k 0002 /k 222 = 0.66), which can be taken as a boundary, below which the structure is considered to be close to the "ideal" 3D crystalline structure (we adopt this relaxed definition for "ideal" after ref. [25] as can hardly be ideal in alloys). It is noticed in Fig.…”

The Effects of Composition and Aging on the Martensite and Magnetic Transformations in Ni-Fe-Ga Ferromagnetic Shape Memory Alloys

“…[20] In fact, diffuse scattering and diffuse maxima that are slightly shifted along ,111. directions from the expected v-phase positions have been observed in Cu-Sn, Zr-Ti, and Ti-Cr. [21,22,23] Figure 4(c) is a dark-field image taken from the cluster of diffuse maxima attributed to the incommensurate ordered v-phase marked with a circle in Figure 4(b). The precipitates are about 10 to 20 nm in diameter.…”