Experimental, modelling and simulation of an approach for optimizing the superplastic forming of Ti-6%Al-4%V titanium alloy

Abstract

The study presents an integrated approach for superplastic forming of Ti-6%Al-4%V titanium alloy. The flow behavior of the studied alloy was investigated using uniaxial constant strain rate tensile tests in a temperature range of 800-900 °C and a strain rate range of 3×10−4-3×10-3s-1. The obtained flow behavior was modeled using the simple Johnson-Cook (S J-C), modified Johnson-Cook (M J-C) and artificial neural network (ANN) models. An assessment study between the constructed models was performed in order to evaluate the predictability of each model. Standard statistical comparative quantities such as correlation coefficient (R), mean absolute relative error (AARE) and the root mean square error (RMSE) were used to ascertain the model viability. The S J-C model proved ineffectual in predicting the flow behavior of Ti-6%Al-4%V alloy. The M J-C and ANN models are able to successfully describe the flow behavior of the alloy. The validity of the model used for the simulation was ascertained by testing the predicted data with the constructed models at a temperature of 875 °C and a strain rate of 2×10-3s-1 using DEFORM 3D finite element simulation (FES). The obtained results from the FES were verified with the experimental results after superplastic forming process. The FES results show the possibility of using uniaxial tensile test data to simulate superplastic forming process of the Ti-6%Al-4%V titanium sheets.

High Strain Rate Superplasticity in Al-Zn-Mg-Based Alloy: Microstructural Design, Deformation Behavior, and Modeling

“…The experimental data obtained by the constant strain rate tests at different deformation temperatures and strain rates were used to construct the Arrhenius-type constitutive hyperbolic equation (ACE) and the artificial neural network (ANN) models [64]. The sequences of building each model were described in detail in the previous works [65,66]. The performance of the constructed models was assessed by calculating the correlation coefficient (R) (Equation (1)), the root mean square error (RMSE) (Equation (2)), and the average absolute relative error (AARE) (Equation (3)) [67,68].…”

Numerical Modeling of Superplastic Punchless Deep Drawing Process of a Ti-6Al-4V Titanium Alloy

“…These models can also describe the strain hardening caused by the static and dynamic growth as well as the evolution of an average grain size. Deformation-microstructure constitutive equations can be found in [6,17,21,22,24,25]. The application of complex superplastic models requires the knowledge of the material data usually designated in the experimental tests.…”

“…The results of numerical simulations of the superplastic forming process of the Ti-6Al-4V titanium alloy are found in [27]. The experimental research and numerical simulations of superplastic forming of the Ti-6Al-4V titanium alloy at different strain rates and in different temperatures are presented in [24,25]. The results of numerical simulations of the high strain rate superplastic forming of the Al-6Mg-0.2Sc alloy are contained in [5].…”

Modelling approach for predicting the superplastic deformation behaviour of titanium alloys with strain hardening/softening characterizations

“…The properties of the Ti-based alloys make it a difficult material to deform at room temperature, with high dependence on parameters like the forming temperature or the strain rate [4]. Superplastic forming (SPF) appears to be a good solution, giving the possibility to reduce the necessary flow stress deformation at high temperature [5][6][7][8][9]. The superplasticity is defined as the ability of a polycrystalline material to display a large elongation prior to failure due to high strain rate sensitivity of the flow stress.…”

“…, figure 6(a).Figure 6(b) shows the m0 values versus strain. The m0 values are fitted by equation(9). Determination of θ At 3×10 −4 s −1 , the reference strain rate of VT6 alloy, the thermal softening impact on the flow stress should be isolated.…”