Relationships of strength to composition and phase constitution for three aged beta titanium alloys

Ductility exhaustion mechanisms in thermally exposed thin sheets of a near-β titanium alloy

“…This may also elucidate the origin of ductility loss at elevated temperatures (Ͼ545 °C) in the ductile region contaminated by diffused oxygen. In this region, it may be considered that oxygen, which occupies preferentially the alpha-phase unit cell by increasing the c lattice with no significant effect on the a lattice, [20,37] results in a solute deficiency of Mo in the alpha phase and enrichment of this element in the beta phase, thus leading to lower ductility. Further examinations of exposed specimens using X-ray techniques are currently being carried out by the authors in order to establish the validity of the partitioning concepts presented here.…”

“…It is speculated here that at intermediate temperatures, Mo partitioning between alpha and beta phases is favored to the extent that the strength of the material decreases, as observed by Gordon and Hagemeyer. [37] The lower the temperature of exposure and the longer the time of aging, the higher the element partitioning and the lower the ductility in the material bulk. This may also elucidate the origin of ductility loss at elevated temperatures (Ͼ545 °C) in the ductile region contaminated by diffused oxygen.…”

“…[35,36,37] In particular, it has been shown that increasing the aging time from 2 to 24 hrs at 538 °C led to a decrease of the beta-lattice dimension, through the enrichment of the ␤-Ti phase with molybdenum. This effect was accentuated when reducing the aging temperature from 593 °C to 482 °C.…”

Effects of α phase precipitation on crevice corrosion and tensile strength in Ti–15Mo alloy

“…A similar microduplex structure was also reported by Makino et al [13] in a Ti-15V-3Cr-3Sn-3Al alloy. Gordon and Hagemeyer [14] reported a case of strengthening by the rule of mixture in Ti-11.5Mo-6Zr-4.5Sn, Ti-3Al-8V-6Cr-4Mo-4Zr, and Ti-8V-8Mo-2Fe-3Al alloys. They [14] showed that the strength of all three alloys increased by increasing the volume fraction of the ␣ phase by aging in the ␣ + ␤ two-phase region.…”

Strength evaluation of α and β phases by nanoindentation in Ti–15Mo alloys with Fe and Al addition

“…[8][9][10] Many studies have dealt with the importance of the a phase for the high strength b titanium alloys and described its strength affected by the alloying elements qualitatively. [11][12][13][14] However, there has not been any published work to describe the strength of the a phase itself quantitatively. Since the a phase is relatively fine in the b matrix, it is difficult to evaluate its strength by the conventional macro-or microVickers hardness measurement.…”