Influence of oxygen content on the forging response of equiaxed (α+β) preform of Ti–6Al–4V: commercial vs. ELI grade

Characterization of the hot deformation behavior of a Ti–22Al–25Nb alloy using processing maps based on the Murty criterion

“…However, during hot working, it is not appropriate or precise to predict the deformation mechanism by relying on the shape of the flow curves only. For instance, the steady state flow curves demonstrate superplasticity or dynamic recovery [13,15]. Likewise, flow softening probably indicates lamellar globularization, dynamic recrystallization or adiabatic heating etc.…”

“…In previous reports, a similar domain at higher temperatures and lower strain rates has also been recorded by Semiatin [18] on the Tie6Ale4 V alloy with lamellar starting structure. It is widely recognized that high peak power dissipation efficiency is often associated with dynamic recrystallization [29] or superplasticity [15,30]. In order to validate whether superplasticity occurs in this domain, high temperature tensile testing has been carried out.…”

The analysis of the hot deformation behaviour of the Ti–3Al–8V–6Cr–4Zr–4Mo alloy, using processing maps, a map of microstructure and of hardness

“…Processing maps made the analysis of the behaviour of the broad spectrum of alloys [3,8,16], especially those of titanium [9][10][11][17][18][19][20][21][22][23][24][25][26][27][28][29][30], in the course of hot working, possible. Several approaches of material modelling, besides of the analysis of the shapes of stress-strain curves [9][10][11][18][19][20][21][22][23][24][25][26] and kinetic analysis [9,10,[18][19][20][21][22]26], used P-maps to aid forging process design [9][10][11]18,19,[21][22][23][24]…”

“…Seshacharyulu et al [10] investigated this titanium alloy with an equiaxed a + b microstructure, with the help of available material models, in the very wide range of a strain rate (0.0003-100 s À1 ) and identified the wide regime of flow instabilities at strain rates higher than 0.1 s À1 , which are manifested as adiabatic shear bands in the a + b range. Prasad et al [20] analyzed the influence of oxygen on the forging response of equiaxed Ti-6Al-4V in the strain rate range of 0.001-100 s À1 using kinetic analysis and P-map and delineated the regimes of flow instability manifested as adiabatic shear bands at strain rates higher than about 1 s À1 in the a + b range. Park et al [21] also implemented a processing map obtained at different true strains into the user-subroutine of DEFORM 2D to evaluate the flow and microstructure stability for pancake forgings, and ascertained good agreement with the microstructures of hot-forged pancakes.…”

The optimal determination of forging process parameters for Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy with thick lamellar microstructure in two phase field based on P-map

“…Generally, the lamellar structure has excellent fracture toughness, creep resistance and crack propagation resistance while the equiaxed structure has good plasticity, low cycle fatigue property, and are easy to be deformed with superplasticity. Taking the disk of compressor and engine blade as instances, they are all the aerospace applications of Ti-6Al-4V alloy by employing ␣ + ␤ forging process (Prasad et al, 2001). However, considering the limited workability and the narrow range of the working parameters of the Ti-alloys (Bruschi et al, 2004), in-depth understanding of the relationship between hot working parameters and microstructure is particularly critical for obtaining defect-free forgings and the improvement of performance and reliability of the forged products (Wanjara et al, 2006).…”