Characterization and Modeling of Twinning in a Titanium Alloy Ti-6Al-4V

2011 ◽  
Vol 702-703 ◽  
pp. 237-240 ◽  
Author(s):  
Frederik Coghe ◽  
Wim Tirry ◽  
Luc Rabet ◽  
Paul van Houtte

The twinning behavior of a commercial Ti-6Al-4V alloy is studied using a combined experimental and numerical approach. An extensive microstructural investigation was performed to identify and quantify the active twin systems. The mechanical behavior as a function of initial texture and strain rate was then modeled using a visco-plastic self-consistent crystal plasticity code (VPSC7). Earlier obtained quasi-static and dynamic data served to fit the parameters of the model, giving good agreement. However, even if the model gave qualitatively good predictions of the stress-strain curves and the texture evolution for the different loadings, the calculated twin fractions differed considerably of the experimental results.

2021 ◽  
Vol 8 ◽  
Author(s):  
Tomas Manik ◽  
Knut Marthinsen ◽  
Kai Zhang ◽  
Arash Imani Aria ◽  
Bjørn Holmedal

In the present work, the deformation textures during flat profile extrusion from round billets of an AA6063 and an AA6082 aluminium alloy have been numerically modeled by coupling FEM flow simulations and crystal plasticity simulations and compared to experimentally measured textures obtained by electron back-scatter diffraction (EBSD). The AA6063 alloy was extruded at a relatively low temperature (350°C), while the AA6082 alloy, containing dispersoids that prevent recrystallization, was extruded at a higher temperature (500°C). Both alloys were water quenched at the exit of the die, to maintain the deformation texture after extrusion. In the center of the profiles, both alloys exhibit a conventional β-fiber texture and the Cube component, which was significantly stronger at the highest extrusion temperature. The classical full-constraint (FC)-Taylor and the Alamel grain cluster model were employed for the texture predictions. Both models were implemented using the regularized single crystal yield surface. This approach enables activation of any number and type of slip systems, as well as accounting for strain rate sensitivity, which are important at 350°C and 500°C. The strength of the nonoctahedral slips and the strain-rate sensitivity were varied by a global optimization algorithm. At 350°C, a good fit could be obtained both with the FC Taylor and the Alamel model, although the Alamel model clearly performs the best. However, even with rate sensitivity and nonoctahedral slip systems invoked, none of the models are capable of predicting the strong Cube component observed experimentally at 500°C.


Author(s):  
Xianfeng Ma ◽  
Kan Ma ◽  
Yawen Wu

For a better use of titanium alloy in nuclear industry, development of integrated computational materials engineering (ICME) model is necessary to optimize alloy microstructure and thus the performance of titanium component. Within an ICME toolset, constitutive models play an important role in quantitatively capturing the interrelationship between processing, microstructure and property. In this paper, texture evolution during hot extrusion of near-alpha Ti6242S bar were studied with respect to the deformation and transformation texture component. Experimentally measured alpha and beta phase textures were instantiated in a three dimensional rate-dependent crystal plasticity model. The model is able to accurately predict the deformation textures of both the alpha and beta phases at extrusion temperature. While decomposition of the metastable beta phase occurred during the post-extrusion cooling, most of the transformation texture components formed aligned [0001] with the extrusion direction, which formed the primary component of extruded alpha texture. The transformation texture was predicted by numerically decomposing the simulated beta texture according to appropriate variant selection rule. Also demonstrated was the capability of a crystal plasticity model incorporating microstructure information, such as phase fraction and lamellar spacing. The crystal plasticity model was validated by comparing with the experimental elastoplasticity behaviors of Ti6242S bars with various microstructures.


2020 ◽  
Vol 277 ◽  
pp. 128329 ◽  
Author(s):  
Y.H. Liu ◽  
Z.B. Zhao ◽  
C.B. Zhang ◽  
Q.J. Wang ◽  
H. Sun ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2021
Author(s):  
Oleksandr Lypchanskyi ◽  
Tomasz Śleboda ◽  
Aneta Łukaszek-Sołek ◽  
Krystian Zyguła ◽  
Marek Wojtaszek

The flow behavior of metastable β titanium alloy was investigated basing on isothermal hot compression tests performed on Gleeble 3800 thermomechanical simulator at near and above β transus temperatures. The flow stress curves were obtained for deformation temperature range of 800–1100 °C and strain rate range of 0.01–100 s−1. The strain compensated constitutive model was developed using the Arrhenius-type equation. The high correlation coefficient (R) as well as low average absolute relative error (AARE) between the experimental and the calculated data confirmed a high accuracy of the developed model. The dynamic material modeling in combination with the Prasad stability criterion made it possible to generate processing maps for the investigated processing temperature, strain and strain rate ranges. The high material flow stability under investigated deformation conditions was revealed. The microstructural analysis provided additional information regarding the flow behavior and predominant deformation mechanism. It was found that dynamic recovery (DRV) was the main mechanism operating during the deformation of the investigated β titanium alloy.


2021 ◽  
Vol 12 ◽  
pp. 63-73
Author(s):  
Ruifeng Dong ◽  
Xiaoyang Zhang ◽  
Hongchao Kou ◽  
Ling Yang ◽  
Yuhong Zhao ◽  
...  

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