Stress relaxation induced spheroidization of the lamellar α phase in Ti-7333 alloy

Jia, Cheng; Kou, Hongchao; Chen, Nengzhen; Liu, S.B.; Fan, Jiangkun; Tang, Bin; Li, J.S.

doi:10.1016/j.jallcom.2018.11.230

Cited by 11 publications

(4 citation statements)

References 24 publications

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“…The corresponding fast Fourier transform (FFT) pattern of the long band along the

zone axis is inserted in the circled area of Figure 5 d. It is found that the band is actually a

twin band. According to previous work [ 15 , 22 , 23 ], the localized shear band ties to the α/β interface and transversely forms across the α plate. The break-up of α plates or namely the β penetration accompanies when grooves deepen.…”

Section: Resultsmentioning

confidence: 92%

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Study on Grain Refinement Mechanisms and Mechanical Properties of bi-Modal Ti-55511 Titanium Alloy during Hot Rolling

et al. 2020

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Multi-pass hot rolling was performed on bi-modal Ti-55511 alloy with 50% rolling reduction at 700 °C. Mechanical properties were evaluated by tensile test, and microstructure evolution was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the Ti-55511 alloy with bi-modal microstructure exhibits good strength and high ductility (1102 MPa, 21.7%). Comparatively, after 50% hot rolling, an enhanced strength and decreased ductility were obtained. The refinement of α phases leads to the increased tensile strength, while the fragmentation of the equiaxed α phase results in a decreased ductility. The fragmentation process of equiaxed α phases followed the sequence of: elongation of α phases → formation of grooves and localized shear bands → the final fragmentation accomplished via deepening grooves.

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“…The corresponding fast Fourier transform (FFT) pattern of the long band along the

zone axis is inserted in the circled area of Figure 5 d. It is found that the band is actually a

Section: Resultsmentioning

confidence: 92%

“…It is found that the band is actually a 1011 twin band. According to previous work [15,22,23], the localized shear band ties to the α/β interface and transversely forms across the α plate. The break-up of α plates or namely the β penetration accompanies when grooves deepen.…”

Section: Mechanical Propertiesmentioning

confidence: 87%

Study on Grain Refinement Mechanisms and Mechanical Properties of bi-Modal Ti-55511 Titanium Alloy during Hot Rolling

et al. 2020

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“…Luo et al [10] have reported that the relaxation rate of a Ti-6Al-4V alloy with an equiaxed structure in the plastic region increases with the decrease in grain size, and the threshold stress in stress relaxation, i.e., constant stress after relaxation reaches steady state, decreases due to the fine grain rotation mechanism. Jia et al [11] have revealed that the relaxation behavior of lamellar titanium alloys after severe plastic compression deformation (>0.7) is accompanied by significant lamellar spheroidization. Wang et al [12] have considered that the interaction between dislocation and α lamella caused by plastic loading in titanium alloys with a lamellar structure is the reason for the slow relaxation rate.…”

Section: Introductionmentioning

confidence: 99%

A Unified Constitutive Model of Stress Relaxation of Ti-6Al-4V Alloy with Different Temperatures from Elastic to Plastic Loading

Zhang

et al. 2022

Machines

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The effects of temperature and pre-strain levels on the stress relaxation behavior and corresponding microstructural evolutions of Ti-6Al-4V alloys have been investigated experimentally and numerically in this study. A series of tests (stress relaxation (SR) and repeated stress relaxation (RSR)) and microstructural observations (scanning electron microscope) have been performed, based on which the deformation-related variables, i.e., stress component and activation energy, as a function of the testing time are calculated according to the classical thermal activation theories. The experimental SR behavior and the obtained thermal related variables show that at lower temperatures (700 °C and 750 °C), a large number of dislocations introduced by plastic loading enhance dislocation slip/climb creep, giving rise to rapid relaxation compared with those with elastic loading conditions at the same temperature. At higher temperatures (800 °C and 850 °C), a similar SR phenomenon has been observed at both elastic and plastic loading conditions, which is due to the severe interaction between diffusion creep and dislocation creep after the loading stage. Based on these results, a unified constitutive equation has been proposed to successfully predict the behavior of the whole stress relaxation process composed of the loading stage and subsequent SR stage. The model considering the continuous evolution of internal variables, e.g., dislocation density and lamellar width, in two stages can predict the stress response and microstructure variation with different temperatures from elastic to plastic loading and provide a foundation to effectively optimize the hot forming process combining pre-deformation and stress relaxation.

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“…He reported that during the process of relaxation, not only did the mobile dislocation density change, but also the residual ¡ phase changed from a lath shape to a spherical shape, and a uniform microstructure was obtained. 13) Yang et al 14) reported that using the traditional constitutive relation to fit the stress relaxation under high experimental temperature will result in the tolerance of the stress relaxation limit for 718 alloy, which is caused by the evolution of microstructure under different temperatures. In addition, these researches mainly focus on the relaxation law of metal materials, but relaxation of the springs which subject to more complex stress states.…”

Section: Introductionmentioning

confidence: 99%

Stress Relaxation Constitutive Relations and Finite Element Analysis of T9A Helical Compression Spring

Nong

Wang²,

Gao³

et al. 2021

Mater. Trans.

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In order to reveal the variation trend of stress in T9A complex helical structure during long period of service, the stress relaxation of T9A helical compression spring was investigated via experiment and finite element analysis. The stress relaxation experiments of the T9A helical compression spring were carried out for up to 30 h at 90°C, 110°C, 130°C and 150°C, and a modified constitutive relation was established on the basis of the experimental data. As a result, it proves that the model is effective to predict the whole relaxation process. Meanwhile, the finite element analysis of the helical structure spring was carried out. It is found that the steel wire in the spring is relaxed from outside to inside in the process of relaxation.

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Stress relaxation induced spheroidization of the lamellar α phase in Ti-7333 alloy

Cited by 11 publications

References 24 publications

Study on Grain Refinement Mechanisms and Mechanical Properties of bi-Modal Ti-55511 Titanium Alloy during Hot Rolling

Study on Grain Refinement Mechanisms and Mechanical Properties of bi-Modal Ti-55511 Titanium Alloy during Hot Rolling

A Unified Constitutive Model of Stress Relaxation of Ti-6Al-4V Alloy with Different Temperatures from Elastic to Plastic Loading

Stress Relaxation Constitutive Relations and Finite Element Analysis of T9A Helical Compression Spring

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