Microstructure determined fracture behavior of a high Nb containing TiAl alloy

Wu, Zhongzhen; Hu, Rui; Zhang, Tiebang; Zhou, Huan; Kou, Hongchao; Li, Jinshan

doi:10.1016/j.msea.2016.04.074

Cited by 33 publications

(3 citation statements)

References 40 publications

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“…It has been well known that the dislocation motion dominates the plastic deformation of metals. With an increase of the temperature, the motion resistance due to Peierls-Nabarro stress is reduced and thus the dislocation motion becomes easier than that at RT [43][44][45]. On the other hand, as the yield strength is sensitive to the Peierls-Nabarro stress [44], and thus the yield strength of materials becomes lower as well.…”

Section: Temperature Dependence Of Fractography With Sem Characteriza...mentioning

confidence: 99%

A Constitutive Relation Based on the Johnson–Cook Model for Ti-22Al-23Nb-2(Mo, Zr) Alloy at Elevated Temperature

et al. 2021

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Although several schemes have been proposed to modify the classical Johnson–Cook (J-C) model, the effect of temperature on the flow stress of materials at different temperatures has not been clarified. In the current study, to investigate the deformation behavior of Ti-22Al-23Nb-2(Mo, Zr) alloy at different temperatures, uniaxial tension experiments were performed at both room (RT, 28 °C) and elevated temperatures, and a modified J-C model was developed to describe the temperature-dependent plastic flow. In tensile experiments, Ti2AlNb-based alloy showed a continuous work hardening until reaching the ultimate strength at RT, while an apparent drop appeared in the flow stress after the peak stress at elevated temperature. Moreover, the experimental peak stress significantly depends on the testing temperature. To correctly describe the different variations of flow stresses at different temperatures, a parameter, S, which represents the softening behavior of flow stress, is integrated into the classical J-C model. In addition, the applicability and validity of the proposed J-C model were verified by calibration with experimental curves of different temperatures. On the other hand, the fractography of post-test specimens was examined to interrupt the increased fracture brittleness of Ti2AlNb-based alloy at elevated temperatures. The proposed constitutive relation based on the J-C model is applicable to predict the deformation behavior of other Ti2AlNb-based alloys at different temperatures.

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Section: Temperature Dependence Of Fractography With Sem Characteriza...mentioning

confidence: 99%

A Constitutive Relation Based on the Johnson–Cook Model for Ti-22Al-23Nb-2(Mo, Zr) Alloy at Elevated Temperature

et al. 2021

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“…Hence, it is important to investigate their fracture behavior during high-cycle fatigue (HCF) for improving the service property of TiAl alloys. Most of the previous researches have been focused on fatigue crack growth [12][13][14][15]. It was demonstrated that the low ductility and toughness of TiAl alloys result in a low tolerance to fatigue crack growth and a relatively steep slope of the Paris region [16,17].…”

Section: Introductionmentioning

confidence: 99%

Effect of Microstructure on the High-Cycle Fatigue Behavior of Ti(43-44)Al4Nb1Mo (TNM) Alloys

Tang

Zhu

et al. 2019

Metals

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To investigate the high-cycle fatigue (HCF) behavior of TNM alloys, three different microstructures were designed and obtained by different heat treatments. Staircase tests and fatigue tests in a finite life-region were performed to evaluate the fatigue properties. Then, the fracture surfaces were analyzed to study the fracture behavior of TNM alloys with different microstructures. Results showed that the TNM alloys with duplex microstructure possesses the highest fatigue strength and fatigue life, followed by near lamellar TiAl alloys. HCF failure exhibited cleavage fracture morphologies, and multiple facets were generated in the crack initiation region of different TNM alloys. Two different crack initiation modes, subsurface crack nucleation and surface origin, were observed. Both crack initiation modes appeared in near lamellar alloys, while only subsurface crack initiation were obtained in the duplex (DP) alloy. It contributes to the high scatter of S-N data. The HCF failure of TNM alloys was dominated by crack nucleation rather than crack propagation. These findings could provide guidance for optimizing the microstructure and improving the HCF properties of TiAl alloys.

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“…Based on the above advantages and their different serving temperatures, the two alloys have become the most promising candidates for hot-section components with temperature gradients in aero-engines [7][8][9]. However, it is difficult to make them into large-scale and complex components, due to their poor workability [10,11]. Therefore, it is significant and necessary to join them together, in order to make full use of their respective advantages and extend their applications.…”

Section: Introductionmentioning

confidence: 99%

Diffusion Bonding of Ti2AlNb Alloy and High-Nb-Containing TiAl Alloy: Interfacial Microstructure and Mechanical Properties

Bian

Lei

Wang

et al. 2018

Metals

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In this study, reliable Ti2AlNb/high-Nb-containing TiAl alloy (TAN) joints were achieved by diffusion bonding. The effects of bonding temperature and holding time on the interfacial microstructure and mechanical properties were fully investigated. The interfacial structure of joints bonded at various temperatures and holding times was characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results show that the typical microstructure of the Ti2AlNb substrate/O phase/Al(Nb,Ti)2 + Ti3Al/Ti3Al/TAN substrate was obtained at 970 °C for 60 min under a pressure of 5 MPa. The formation of the O phase was earlier than the Al(Nb,Ti)2 phase when bonding temperature was relatively low. When bonding temperature was high enough, the Al(Nb,Ti)2 phase appeared earlier than the O phase. With the increase of bonding temperature and holding time, the Al(Nb,Ti)2 phase decomposed gradually. As the same time, continuous O phase layers became discontinuous and the Ti3Al phase coarsened. The maximum bonding strength of 66.1 MPa was achieved at 970 °C for 120 min.

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Microstructure determined fracture behavior of a high Nb containing TiAl alloy

Cited by 33 publications

References 40 publications

A Constitutive Relation Based on the Johnson–Cook Model for Ti-22Al-23Nb-2(Mo, Zr) Alloy at Elevated Temperature

A Constitutive Relation Based on the Johnson–Cook Model for Ti-22Al-23Nb-2(Mo, Zr) Alloy at Elevated Temperature

Effect of Microstructure on the High-Cycle Fatigue Behavior of Ti(43-44)Al4Nb1Mo (TNM) Alloys

Diffusion Bonding of Ti2AlNb Alloy and High-Nb-Containing TiAl Alloy: Interfacial Microstructure and Mechanical Properties

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