Effect of cyclic stress on the high temperature creep behavior of AlMg alloys

Yang, Zhi'an; Wang, Zhirui; Hu, Xiaobo; Zhongguang, Wang

doi:10.1016/0956-7151(93)90027-p

Cited by 15 publications

(5 citation statements)

References 29 publications

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“…In these materials, it was found that an increase conditions yielded a contradictory result, e.g., the dislocation in prestrain from 0.3 to 1.6 pct considerably changed the configuration changed from cell structures to patches when cyclic softening behavior. [13] It has been reported that these closely related to each other. [6,7] Up until now, the studies on cyclic creep were mainly because many springs are made with cold-drawn and/or performed under conditions of pull-pull and pull-zero cyclic hard-drawn wires/rods, which are plastically deformed durstresses.…”

Section: Introductionmentioning

confidence: 93%

“…For example, the results als are also strongly depend on the history of plastic on a low-carbon steel subjected to cyclic testing under symdeformation. [12,13] Conventional judgment on setting, and shot peening, [8] as well as the possible overload the micromechanism of cyclic creep is that the dislocation events in service, may all introduce plastic deformation in structures in cyclic creep are similar to those in static creep the spring materials. [9] However, another result in apparent cyclic softening in as-received hot-rolled study on a hot-rolled spring steel under various cyclic creep spring steels.…”

Section: Introductionmentioning

confidence: 99%

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Cyclic creep and cyclic deformation of high-strength spring steels and the evaluation of the sag effect: Part I. Cyclic plastic deformation behavior

Yang

Wang

2001

Metall Mater Trans A

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The cyclic creep and cyclic plastic deformation behavior of two commercial suspension spring steels of high hardness levels, namely, SAE 9259 and SAE 5160, were studied under different testing conditions of cyclic peak stress and cyclic stress ratio. The experimental results indicate that both the cyclic stress ratio and cyclic peak stress have strong, but complicated, effects on the cyclic creep and cyclic plastic deformation behavior of these materials. It has also been found that the addition of silicon can increase the resistance of these steels to cyclic creep and cyclic plastic deformation, although the extent of this increase is also related to other cyclic deformation conditions. A transition in the relationship between the total plastic strain range and the cyclic stress ratio (R) has been detected at approximately R ϭ 0.5. The mechanism of such a transition is explained by the operation of cross-slip during the unloading process of cycling. Moreover, a cyclic softening behavior of these spring steels in the quench-tempered condition was also detected and is attributed to the activation and reorganization of obstacle dislocations introduced into the steels during the process of martensitic transformation. More importantly, this study has indicated that parameters such as the cyclic creep strain, the cyclic creep rate in the secondary creep stage, and the total cyclic plastic strain range can better reflect, and should be used to depict and characterize, the sag behavior of spring steels as well as other materials. Finally, the effect of silicon on sag behavior, in comparison with the results from the Bauschinger-effect test, has also been discussed through the influence of Si on carbide formation and distribution.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Cyclic creep and cyclic deformation of high-strength spring steels and the evaluation of the sag effect: Part I. Cyclic plastic deformation behavior

Yang

Wang

2001

Metall Mater Trans A

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“…The interaction of the dislocations gives rise to dislocation pile-up, dislocation tan- gling, and immovable jog [19] (Fig.6c, 6d), and a gradual increase in flow stress. Studies have shown that [20,21] , the dislocation in the material accelerates with the increase of strain rate under dynamic load conditions. Meanwhile, "short range factors" (such as the Peierl-Nabarro force between lattices, the atomic thermal vibration resistance, atomic extra-nuclear electron cloud resistance) that block dislocations are significantly enhanced.…”

Section: Dislocation Motion Mechanism During Dynamic Tensile Loadingmentioning

confidence: 99%

Dynamic Tensile Properties and Deformational Mechanism of C5191 Phosphor Bronze

Dao-chun

Chen

2017

Rare Metal Materials and Engineering

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To observe the dynamic mechanical response and investigate the processes of high speed stamping for C5191 phosphorus bronze, tensile tests of C5191 phosphor bronze under quasi-static tensile condition at a strain rate of 0.001 s-1 by electronic universal testing machine, and dynamic tensile tests at strain rates of 500, 1000 and 1500 s-1 by split Hopkinson tensile bar (SHTB) apparatus were performed. The dynamic tensile properties and deformational mechanism were investigated by SEM and TEM. The results show that the yield strength and tensile strength of C5191 phosphor bronze under high strain rates increase by 32.77% and 11.07%, respectively compared with quasi-static condition, the strain hardening index increases from 0.075 to 0.251, and the strain rate sensitivity index for material strength changes from 0.005 to 0.022, which presents a clear sensitivity to strain rates. The deformation resistance increases with the increasing of the strain rate due to the stronger short range resistance induced by the acceleration of dislocation motion. The ability of plastic deformation of C5191 phosphor bronze increases due to the number of movable dislocations increase significantly, multi-line slip start, and the soft effect of adiabatic temperature rise at the strain rate ranging from 500 to 1500 s-1 .

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“…However, some tremendous obstacles must be overcome to improve the performance of these devices further, such as the radio frequency (RF) drain current collapse and other reliability problems [2,3] . The parasitic effects are considered to be mainly caused by the trapping centers due to the defects or impurities in the device materials, and a lot of energy and efforts have been devoted into the trapping phenomena research [4][5][6][7][8][9][10][11][12][13][14][15][16][17] . By carrying out the turn-on pulse transient tests or simulation, the surface, interface or bulk traps have been investigated, respectively [3][4][5][6][7][8][9][10] .…”

Section: Introductionmentioning

confidence: 99%

Coeffect of trapping behaviors on the performance of GaN-based devices

et al. 2018

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Trap-induced current collapse has become one of the critical issues hindering the improvement of GaN-based microwave power devices. It is difficult to study the behavior of each trapping effect separately with the experimental measurement. Transient simulation is a useful technique for analyzing the mechanism of current collapse. In this paper, the coeffect of surface- and bulk-trapping behaviors on the performance of AlGaN/GaN HEMTs is investigated based on the two-dimensional (2D) transient simulation. In addition, the mechanism of trapping effects is analyzed from the aspect of device physics. Two simulation models with different types of traps are used for comparison, and the simulated results reproduced the experimental measured data. It is found that the final steady-state current decreases when both the surface and bulk traps are taken into account in the model. However, contrary to the expectation, the total current collapse is dramatically reduced (e.g. from 18% to 4% for the 90 nm gate-length device). The results suggest that the surface-related current collapse of GaN-based HEMTs may be mitigated in some degree due to the participation of bulk traps with short time constant. The work in this paper will be helpful for further optimization design of material and device structures.

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Effect of cyclic stress on the high temperature creep behavior of AlMg alloys

Cited by 15 publications

References 29 publications

Cyclic creep and cyclic deformation of high-strength spring steels and the evaluation of the sag effect: Part I. Cyclic plastic deformation behavior

Cyclic creep and cyclic deformation of high-strength spring steels and the evaluation of the sag effect: Part I. Cyclic plastic deformation behavior

Dynamic Tensile Properties and Deformational Mechanism of C5191 Phosphor Bronze

Coeffect of trapping behaviors on the performance of GaN-based devices

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