Behavior and modeling of flow softening and ductile damage evolution in hot forming of TA15 alloy sheets

Yang, Lei; Wang, Baoyu; Liu, Gang; Zhao, Huijun; Xiao, Wenchao

doi:10.1016/j.matdes.2015.06.096

Cited by 66 publications

(20 citation statements)

References 39 publications

(48 reference statements)

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“…16 (b)), indicating that strain-induced transformation of α to β occurred during the globularization process of secondary α. Similar results were also reported by Yang et al [30] and Zhao et al [25]. With the increasing of bulging ratio, lot of DRX occurred in the equiaxed α and the grain size decreased obviously after the bulging (Fig.…”

Section: Accepted Manuscriptsupporting

confidence: 89%

Correlation between softening mechanisms and deformation non-uniformity of laser-welded titanium alloy tube during gas bulging process

Wang

Liu

Politis

et al. 2017

Materials Characterization

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In this paper, post-weld annealing was carried out to adjust the flow stress difference between weld seam and base material (BM). Deformation non-uniformity of laser-welded titanium alloy tubes before and after annealing was evaluated by gas bulging at 800 °C. Results show that after double annealing (950 °C/2 h, air cooling + 600 °C / 2 h, air cooling), weld seam and BM had similar peak stress at first during tensile test at 800 °C, 0.001 s− 1, then the flow stress difference between them changed dynamically due to different softening rates. The maximum flow stress difference ratio was reduced from 36% to 17% after annealing. Deformation uniformity of the bulged tube was improved by 24.6% after annealing, but the higher softening rate of BM during gas bulging confined its further improvement. At early stage of gas bulging of the annealed tube, the main softening mechanism for weld seam was dynamic recovery and that for BM was globularization of secondary α and phase transformation of α to β. At middle-late stage of gas bulging, the main softening mechanism for weld seam was partial globularization of lamella α and that for BM was wide dynamic recrystallization

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Section: Accepted Manuscriptsupporting

confidence: 89%

Correlation between softening mechanisms and deformation non-uniformity of laser-welded titanium alloy tube during gas bulging process

Wang

Liu

Politis

et al. 2017

Materials Characterization

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“…The unified viscoplastic constitutive equations were developed to predict flow stress and microstructure evolution for many types of metal materials [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. Recovery, recrystallization, grain size, and dislocation density were well described in the framework of the unified viscoplastic constitutive model.…”

Section: Constitutive Equations and Microstructural Model Of 21-4nmentioning

confidence: 99%

Predicting the Microstructure of a Valve Head during the Hot Forging of Steel 21-4N

Huang

et al. 2018

Metals

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Abstract:Valve microstructure is important during hot forging. Austenitic 21-4N steel is often used in exhaust valves. In this study, the microstructure evolution of the forging valve process was predicted using the internal state variables (i.e., average grain size, recrystallized fraction, and dislocation density) modus for 21-4N. First, 21-4N was subjected to hot compression tests on a Gleeble-1500D and static grain growth tests in a heating furnace. A set of uniform viscoplastic constitutive equations was established based on experimental data. Next, the determined unified constitutive equations were conducted in DEFORM-3D, and the microstructure evolution of 21-4N during forging was calculated. Finally, the simulation results of grain size evolution were validated via experiments. Results showed good consistency between the simulations and experiments. Thus, the models adequately predicted the microstructure evolution.

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“…3 Deformation mechanisms 3.1 True stress-train curves Fig. 3 shows the true stress-strain curves, which were calculated from the loaddisplacement recorded by the hot tensile machine [35] . It is clear that the flow stress decreases with increasing deformation temperature and decreasing strain rate.…”

Section: Uniaxial Hot Tensile Testsmentioning

confidence: 99%

“…Lin et al [32] developed a set of generalized constitutive equations to reveal the nucleation and growth of the damage. This set of equations has been successfully applied to many types of materials [33][34][35] . Huo et al [33] developed a multiaxial constitutive model coupling the microstructure and ductile damage of a high-speed railway axle steel during cross wedge rolling, the result showed that the developed model can reliably predict the grain size and ductile damage evolution.…”

Section: Introductionmentioning

confidence: 99%

“…Xiao et al [34] studied the flow behaviour and ductile damage of AA7075 aluminium alloy by developing a constitutive model coupled with the evolution of dynamic crystallization, grain size and damage. Yang et al [35] formulated a set of constitutive equations to investigate the underlying mechanism of flow softening and ductile damage of TA15 titanium alloy in sheet forming.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Behaviour and constitutive modelling of ductile damage of Ti-6Al-1.5Cr-2.5Mo-0.5Fe-0.3Si alloy under hot tensile deformation

Wang

Huang

et al. 2019

Journal of Alloys and Compounds

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In this paper, the flow softening and ductile damage of TC6 alloy were investigated using a uniaxial hot tensile test with deformation temperatures of 910 °C~970 °C and strain rates of 0.01 s-1~1 0 s-1. Scanning electron microscopy (SEM) was performed on the deformed specimens to reveal the damage mechanism. The results showed that the flow stress rapidly increases to a peak at a tiny strain, followed by a significant decrease due to flow softening and ductile damage. The ductile damage of the studied TC6 alloy can be ascribe to the nucleation, growth and coalescence of microdefects, and the microvoids preferentially nucleate at the interface of the alpha phase and beta matrix due to the inconsistent strain. Then, a set of unified viscoplastic constitutive equations including flow softening and ductile damage mechanisms was developed and determined, and this set of equations was verified by the experimental flow stress, which indicated the reliability of the prediction. Furthermore, the predicted normalized dislocation density and the adiabatic temperature rise increase with decreasing temperature and increasing strain rate. The predicted damage components show that the microdefects mainly nucleate in the initial stage, but then primarily grow 2 and link together with continuing deformation.

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Behavior and modeling of flow softening and ductile damage evolution in hot forming of TA15 alloy sheets

Cited by 66 publications

References 39 publications

Correlation between softening mechanisms and deformation non-uniformity of laser-welded titanium alloy tube during gas bulging process

Correlation between softening mechanisms and deformation non-uniformity of laser-welded titanium alloy tube during gas bulging process

Predicting the Microstructure of a Valve Head during the Hot Forging of Steel 21-4N

Behaviour and constitutive modelling of ductile damage of Ti-6Al-1.5Cr-2.5Mo-0.5Fe-0.3Si alloy under hot tensile deformation

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