Elevated-Temperature Mechanical Behavior of As-Cast and Wrought Ti-6Al-4V-1B

Abstract

This work studied the effect of processing on the elevated-temperature [728 K (455°C)] fatigue deformation behavior of Ti-6Al-4V-1B for maximum applied stresses between 300 to 700 MPa (R = 0.1, 5 Hz). The alloy was evaluated in the as-cast form as well as in three wrought forms: cast-and-extruded, powder metallurgy (PM) rolled, and PM extruded. Processing caused significant differences in the microstructure, which in turn impacted the fatigue properties. The PM-extruded material exhibited a fine equiaxed a + b microstructure and the greatest fatigue resistance among all the studied materials. The b-phase field extrusion followed by cooling resulted in a strong a-phase texture in which the basal plane was predominately oriented perpendicular to the extrusion axis. The TiB whiskers were also aligned in the extrusion direction. The a-phase texture in the extrusions resulted in tensile-strength anisotropy. The tensile strength in the transverse orientation was lower than that in the longitudinal orientation, but the strength in the transverse orientation remained greater than that for the as-cast Ti-6Al-4V. The ratcheting behavior during fatigue is also discussed.

Research Progress on the Creep Resistance of High-Temperature Titanium Alloys: A Review

“…Boehlert C J, et al [108] showed that the creep resistance of as-cast Ti-6Al-4V-1B alloy was significantly better than that of Ti-6Al-4V-0.1B alloy, and the steady-state creep rate was, at least, one order of magnitude lower than that of as-cast Ti-6Al-4V alloy. Chen W, et al [109] investigated the as-cast Ti-6Al-2Sn-4Zr-2Mo-0.1Si alloy and showed that the addition of B could also improve the high-temperature creep resistance of the alloy, but the improvement's effect was not as obvious as that of Ti-6Al-4V alloy.…”

A comparison of field assisted hot pressing and hot isostatic pressing for gas atomized Ti–22Al–26Nb(at.%) and Ti–22Al–26Nb–5B(at.%) powders

“…The addition of small amounts of B to Ti2AlNb and TiAl intermetallics and conventional Ti alloys, such as Ti-6Al-4V(wt.%) and Ti-6Al-2Sn-4Zr-2Mo-0.1Si(wt.%), has been shown to significantly decrease the grain size and/or lamellar spacing leading to significant benefits including increasing tensile strength and fatigue and creep resistance [9,20,[41][42][43][44][45][46][47][48][49][50]. In addition, it reduces the time spent on expensive and energy-intensive thermomechanical processing used to 1 henceforth all compositions will be given in atomic percent unless otherwise specified.…”