Temperature dependent flow softening of titanium alloy Ti6Al4V: An investigation using finite element simulation of machining

Karpat, Yiğit

doi:10.1016/j.jmatprotec.2010.12.008

Cited by 134 publications

(56 citation statements)

References 28 publications

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“…K), and heat capacity C p (T) = 2.7e 0.0002T (N/mm 2 /°C) [35]. The heat transfer coefficient at the tool-chip interface is taken as a constant 5000 W/ m 2°C .…”

Section: Finite Element Simulation Model Of Microscale Machiningmentioning

confidence: 99%

Investigating the influence of friction conditions on finite element simulation of microscale machining with the presence of built-up edge

Oliaei

2016

Int J Adv Manuf Technol

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In micromachining, the uncut chip thickness is less than the cutting tool edge radius, which results in a large negative effective rake angle. Depending on the material properties, this large negative rake angle promotes built-up edge (BUE) formation. A stable BUE acts like a cutting edge and affects the mechanics of the process. The size of the BUE increases with increasing uncut chip thickness and cutting speed. It also creates a positive rake angle, but it decreases the clearance angle of the tool. A method of including BUE formation in finite element simulations is to use sticking friction conditions at the tip of the tool. However, this approach is shown to be insufficient to simulate BUE formation in microscale machining. Therefore, the cutting edge is modified with the experimental BUE size in the finite element simulations based on experimental measurements. The influence of friction models between BUE and the work material has been investigated, and the study identifies friction coefficients that yield good agreements with experimental results. The finite element model is shown to be capable of simulating process forces and chip shapes for uncut chip thickness values larger than minimum uncut chip thickness.

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“…K), and heat capacity C p (T) = 2.7e 0.0002T (N/mm 2 /°C) [35]. The heat transfer coefficient at the tool-chip interface is taken as a constant 5000 W/ m 2°C .…”

Section: Finite Element Simulation Model Of Microscale Machiningmentioning

confidence: 99%

Investigating the influence of friction conditions on finite element simulation of microscale machining with the presence of built-up edge

Oliaei

2016

Int J Adv Manuf Technol

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“…Shafaat et al (2011) proposed an empirical flow stress model for Ti-6Al-4V by combining the Cingara model during hardening up to the peak stress and a softening model identical to JMAK equation thereafter. A similar approach was followed by Karpat (2011) by mixing a modified Johnson-Cook model for hardening and a hyperbolic model for softening which is used during machining simulation of Ti-6Al-4V. Porntadawit et al (2014) incorporated the Cingara model for hardening and the Shafiei-Ebrahimi model for softening by dynamic recrystallization.…”

Section: State Of the Art In Models For Ti-6al-4vmentioning

confidence: 99%

A model for Ti–6Al–4V microstructure evolution for arbitrary temperature changes

Murgau

Pederson

Lindgren

2012

Modelling Simul. Mater. Sci. Eng.

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This thesis is devoted to microstructure modelling of Ti-6Al-4V. The microstructure and the mechanical properties of titanium alloys are highly dependent on the temperature history experienced by the material. The developed microstructure model accounts for thermal driving forces and is applicable for general temperature histories. It has been applied to study wire feed additive manufacturing processes that induce repetitive heating and cooling cycles. The microstructure model adopts internal state variables to represent the microstructure through microstructure constituents' fractions in finite element simulation. This makes it possible to apply the model efficiently for large computational models of general thermomechanical processes. The model is calibrated and validated versus literature data. It is applied to Gas Tungsten Arc Welding -also known as Tungsten Inert Gas welding-wire feed additive manufacturing process. Four quantities are calculated in the model: the volume fraction of phase, consisting of Widmanstätten , grain boundary , and martensite . The phase transformations during cooling are modelled based on diffusional theory described by a Johnson-Mehl-AvramiKolmogorov formulation, except for diffusionless martensite formation where the Koistinen-Marburger equation is used. A parabolic growth rate equation is used for the to transformation upon heating. An added variable, structure size indicator of Widmanstätten , has also been implemented and calibrated. It is written in a simple Arrhenius format. The microstructure model is applied to in finite element simulation of wire feed additive manufacturing. Finally, coupling with a physically based constitutive model enables a comprehensive and predictive model of the properties that evolve during processing.

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“…Karpat [13] proposed various temperature-dependent flow softening scenarios which were tested using finite element simulations. The results were compared with experimental data from the literature: flow softening initiating around 350-500 1C combined with appropriate softening parameters yields simulation outputs in good agreement with the experimental measurements.…”

Section: Introductionmentioning

confidence: 99%

Analysis of adiabatic shear banding in orthogonal cutting of Ti alloy

Miguélez¹,

Soldani²,

Molinari³

2013

International Journal of Mechanical Sciences

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This work is focused on the numerical analysis of adiabatic shear banding in orthogonal cutting of Ti6Al4V alloy. Segmented chip results from adiabatic shear banding, depending on the competition of thermal softening and strain and strain rate hardening. The influence of cutting velocity and feed in the chip segmentation is studied. Also the role of friction at the tool-chip interface and the effect of rheological parameters of the constitutive equation are analyzed. Experimental tests obtained from previous work of the authors [Molinari A, Musquar C, Sutter G, Adiabatic shear banding in high speed machining of Ti-6Al-4V experiments and modeling, Int J Plast, vol. 18, 2002, p. 443-459] and others were used as a reference to validate the models. Cutting forces and the mechanism of plastic flow localization are analyzed in terms of frequency of segmentation and shear band width and compared to experimental data.

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Temperature dependent flow softening of titanium alloy Ti6Al4V: An investigation using finite element simulation of machining

Cited by 134 publications

References 28 publications

Investigating the influence of friction conditions on finite element simulation of microscale machining with the presence of built-up edge

Investigating the influence of friction conditions on finite element simulation of microscale machining with the presence of built-up edge

A model for Ti–6Al–4V microstructure evolution for arbitrary temperature changes

Analysis of adiabatic shear banding in orthogonal cutting of Ti alloy

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