Effect of multipass deformation at elevated temperatures on the flow behavior and microstructural evolution in Ti-6Al-4V

Guo, Baoqi; Aranas, Clodualdo; Foul, Anes; Ji, Xiankun; Fall, Ameth; Jahazi, Mohammad; Jonas, John J.

doi:10.1016/j.msea.2018.05.058

Cited by 20 publications

(5 citation statements)

References 21 publications

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“…In addition, at the same finishing temperature and strain rate, the stresses in each pass do not show significant change with the interval time. However, under diminishing temperature conditions with the constant pass true strain of 0.183, the interpass softening is enhanced at the interval time of 5 s. is result is dissimilar to that under the isothermal multipass deformation; that is, longer interval time causes less softening [21]. e flow softening during nonisothermal multipass deformation is the net result of microstructure softening by recrystallization and hardening by accumulative strain; therein, the flow hardening is due to the decrease in temperature.…”

Section: Multipass Flow Behaviormentioning

confidence: 89%

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Constitutive Characteristics, Microstructure, and Texture Evolution of As‐Cast 42CrMo Alloy in Nonisothermal Multipass Compression

Qin

Liu

et al. 2021

Advances in Materials Science and Engineering

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The nonisothermal multipass deformation behavior of as-cast 42CrMo alloy was studied with declining temperature, constant pass strain, varying strain rate, and interval time. The stresses are used to develop the constitutive model. As the finishing temperature increases from 990°C to 1070°C, the stress decreases gradually and the softening effect increases, which results in a large grain size and inhomogeneous microstructure. The low angle grain boundaries transform into high angle grain boundaries through absorbing dislocations. The noticeable stress softening in a high strain rate is attributed to the thermal softening, dynamic recovery, and dynamic recrystallization. The thermal softening is no longer considered to be the main interpass softening mechanism at a low strain rate. The interval time has a negligible effect on the stress, but the significant changes in grain size and texture component are caused by the interpass softening. The average grain size is approximately 40 μm, and the distorted grain boundaries and small fine grains are found in the interval times of 0.5–5 s, implying the dynamic recovery and grain growth. The near {001}<110> and {110}<112> orientation exerts an important influence on the grain refinement.

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Section: Multipass Flow Behaviormentioning

confidence: 89%

“…e graphite foils with a thickness of 0.5 mm were positioned between the specimen and anvils to reduce the contact friction [20]. A thermocouple was welded to the center of each sample to allow the temperature to be tracked and the load-stroke data to be collected with accuracy [21].…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Constitutive Characteristics, Microstructure, and Texture Evolution of As‐Cast 42CrMo Alloy in Nonisothermal Multipass Compression

Qin

Liu

et al. 2021

Advances in Materials Science and Engineering

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“…For NIR strategies, an interpass time (delay time) of 10 s was involved in compensating for the required period for transferring the plates from the rough deformation stands to the finish deformation stands. This moderate value of the interpass time results in less softening [ 18 ] and reduces the total production time. The post-heat treatment is excluded to reduce the time and cost of production.…”

Section: Methodsmentioning

confidence: 99%

“…Guo et al [ 18 ] studied the influence of interpass time during multipass hot torsion testing of Ti-6Al-4V alloy in an α + β range from 2 s to 32 s under continuous cooling cases. They found that less flow softening takes place at longer interpass times.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hot-Rolling Strategy on the Flow Behavior, Productivity, and Mechanical Performance of Ti-6Al-4V Alloy

2022

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This work involves studying the effects of applying various designed hot-rolling strategies, using the uniaxial hot compression regimes of the Gleeble 3500 thermo-mechanical simulator on the microstructure, flow behavior, and productivity of Ti-6Al-4V alloy. These strategies were then practically implemented using a rolling mill to produce finished sheets with a thickness of 3 mm. The tensile properties of these finished Ti-6Al-4V sheets were examined, aiming at attaining the optimum rolling strategy conditions that result in upgrading the mechanical performance of the alloy. The undertaken hot-rolling strategies can be divided into two main groups; both comprise applying a total amount of deformation of 75% at a constant strain rate of 0.1 s−1. The first group, isothermal hot rolling regime (IR), includes three strategies and involves applying the total amount of deformation at constant temperatures, i.e., 900, 800, and 750 °C. The second group, non-isothermal hot rolling regime (NIR), includes three strategies and involves partitioning the total amount of deformation into multi-step deformation at variable temperatures in a range of 900–750 °C. The dynamic flow softening is dominant in all IR strategies after the flow stress attains the peak at a low strain value. Then, dynamic flow softening occurs due to the dynamic recrystallization and α phase spheroidization, while a combination of flow softening and hardening takes place on the different passes of the NIR strategies. The designed hot-rolling strategies result in finished sheets with a fine multimodal microstructure that fructifies different mechanical properties that can be employed for different industrial purposes.

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“…The observations have covered a range of strain rates (including superplastic and non-superplastic), types of deformation (monotonic vs multistage with interpass dwells), and starting microstructures (equiaxed vs colony a). [179][180][181][182] Dynamic transformation in titanium alloys deserves additional attention both as a fundamental phenomenon and with regard to its effect on industrial processing. For example, quantitative in-situ (synchrotron) studies may help to clarify the kinetics of such transformations.…”

Section: Dynamic Transformation Of A/b Titanium Alloysmentioning

confidence: 99%

An Overview of the Thermomechanical Processing of α/β Titanium Alloys: Current Status and Future Research Opportunities

Semiatin

2020

Metall Mater Trans A

155

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Current understanding of the principles underlying the thermomechanical processing (TMP) of a/b titanium alloys is reviewed. Attention is focused on the formulation of constitutive descriptions for plastic flow under hot-working conditions, the evolution of microstructure, the occurrence of defects, and novel/emerging TMP techniques. With regard to constitutive behavior, descriptions of the plastic flow of the individual phases and two-phase alloys per se are summarized. The important influence of phase morphology, size, and volume fraction on plastic flow is emphasized. Mechanisms which underlie microstructure evolution include beta recrystallization (in the high-temperature b field), the development of dislocation substructure and its effect on dynamic and static spheroidization of colony microstructures (in the two-phase field), static and dynamic coarsening of primary a, and the development of deformation and transformation textures. In the area of defects, the effect of TMP variables and starting microstructure on the formation of cavities, the persistence of microtexture, and the development of undesirably-coarse b grain structures are described. The current status of relatively new processing techniques for a/b titanium alloys such as low-temperature superplastic forming and solid-state joining (via linear friction or friction-stir methods) are also briefly reviewed. Last, R&D which could help to resolve deficiencies in the current knowledge base for TMP of a/b titanium alloys are summarized for each of the areas.

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Effect of multipass deformation at elevated temperatures on the flow behavior and microstructural evolution in Ti-6Al-4V

Cited by 20 publications

References 21 publications

Constitutive Characteristics, Microstructure, and Texture Evolution of As‐Cast 42CrMo Alloy in Nonisothermal Multipass Compression

Constitutive Characteristics, Microstructure, and Texture Evolution of As‐Cast 42CrMo Alloy in Nonisothermal Multipass Compression

Effect of Hot-Rolling Strategy on the Flow Behavior, Productivity, and Mechanical Performance of Ti-6Al-4V Alloy

An Overview of the Thermomechanical Processing of α/β Titanium Alloys: Current Status and Future Research Opportunities

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