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International Journal of Minerals,Metallurgy and Materials 2021年第1期28卷 131-141页

作者： Gao-hui Li Li Zhou Ling-yun Luo Xi-ming Wu Ning Guo State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology(WeihaiWeihai)264209China

In this study, we used the stop-action technique to experimentally investigate the material flow and microstructural evolution of alclad 2A12-T4 aluminum alloy during refill friction stir spot *** are two material flow components, i.e., the inward-or outward-directed spiral flow on the horizontal plane and the upward-or downward-directed flow on the vertical *** the plunge stage, the flow of plasticized metal into the cavity is similar to that of a stack, whereby the upper layer is pushed upward by the lower *** the refill stage, this is process *** such, there is no obvious vertical plasticized metal flow between adjacent *** leads to the coarsening of S(Al2CuMg) in the thermo-mechanically affected zone and the diminishing of S in the stir *** dynamic recrystallization results in the formation of fine equiaxed grains in the stir zone, but this process becomes difficult in the thermo-mechanically affected zone due to the lower deformation rate and the pinning action of S precipitates on the dislocations and sub-grain boundaries, which leads to a high fraction of low-angle grain boundaries in this zone.

关键词： refill friction stir spot welding aluminum alloy material flow behavior precipitate evolution dislocation configuration

Enhanced Damping Capacities of Mg–Ce Alloy by the Special Microstructure with Parallel Second Phase

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Journal of Materials Science & Technology 2017年第9期33卷 941-946页

作者： Zhongshan Wu Jingfeng Wang Haibo Wang She Ma Song Huang Shun Li Fusheng Pan National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing University The State Key Laboratory of Mechanical Transmission Chongqing University Institute of Applied Electronics China Academy of Engineering Physics

Microstructure evolution and damping capacities of Mg–Ce binary alloys with three different Ce contents（0.5, 1, or 2 wt%） have been systematically investigated in this work. Numerous fine parallel second phases in Mg–2Ce alloy are obtained, as well as a large number of dislocations around them, but few dislocations appear around the reticular second phase in the Mg–1Ce alloy. Among the three alloys, two internal friction peaks（P;and P;） are detected at about 78 and 167?C in both the Mg–0.5Ce and Mg–1Ce *** addition, the alloy with special parallel second phase structure exhibits excellent damping capacity in both strain amplitude and temperature-dependent regions. These results may be ascribed to the stress concentration and the formation of abundant parallel and uniform dislocation configurations in the ?-Mg matrix without the influence of crystal orientation. The obtained results may provide a novel idea to prepare high-damping magnesium alloys by tailoring their microstructure.

关键词： Mg–Ce alloy Parallel second phase dislocation configuration Damping capacity

CYCLIC DEFORMATION BEHAVIOR OF ZIRCALOY-4 AT DIFFERENT TEMPERATURES

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Acta Metallurgica Sinica(English Letters) 1995年第3期8卷 219-225页

作者： XIAO Lin GU Haicheng KUANG Zhenbang(Xi’an Jiaotong University, China Xi'an Jiaotong Univ Xi'an China

Fatigue lifetime curves of Zircaloy-4 at different temperatures were measured, and the fatigued dislocation configurations were investigated using transmission electron microscopy. Ii was found that prismatic slip is the primary deformation mode. for Zircaloy-4fatigued at RT prismatic plus Pyramidal slip at 400℃,and prismatic plus (0001) basic slip at 600℃. The corresponding dislocation configurations are parallel dislocation lines al RT, elongated cells at 400℃ and two sets of mutually Perpendicular dislocation bands at 600℃.respectively. The relationship among. fatigue deformation mode, dislocation configuration and lifetime is discussed.

关键词： Zircaloy-4,.fatigue dislocation configuration slip system

Effects of Strain Rate on dislocation for TA15 Alloy during Hot Compressive Deformation

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Journal of Wuhan University of Technology(Materials Science) 2011年第2期26卷 187-190页

作者：刘勇 School of Materials Science and Engineering Harbin Institute of Technology

The effects of strain rate on the dislocation type and dislocation configure of TA15 alloy were *** experimental results show that the operating dislocation type changes from c type to c and a＋ c type with increasing strain rate under the deformation condition of 900℃,60% *** the condition of 900℃,60% strain and 0.001/s strain rate,lots of orientate dislocation cellular configurations and sub-grains,many dislocations pile up before sub *** the strain rate increases to 0.1/s,some dislocations exhibit curved and dislocation tangles and pile-ups can be found,suggesting more dislocations and much stronger interactions among dislocations.

关键词： TA15 alloy hot deformation dislocation type dislocation configuration strain rate

IN-SITU OBSERVATION OF CRACK TIP DEFORMATION IN A DUPLEX STAINLESS STEEL

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Acta Metallurgica Sinica(English Letters) 1989年第6期2卷 433-438页

作者： YAO Kefu TANG Naiyong CHEN Nanping Tsinghua University,Beijing,China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A213—A218, Ph.D.Student,Dept.of Materials Sci.and Eng.,Tsinghua University,Beijing,China

The development of dislocation structures in the plastic zone ahead of a crack tip has been in- vestigated in a duplex stainless steel during in-situ deformation experiments in a scanning transmission electron *** was found that the dislocation distribution was significantly different in the ferrite and in the *** the ferrite grains,the dislocations emitted by the crack tip may cross-slip out of the original slip planes and form a broad plastic ***,in the austenite,the dislocation free zone is small and the dislocations emitted by the crack pile up in its slip *** selection of slip systems at the crack tip depends on the crack tip Schmid factors in both *** after large deformation,the selection of the second slip systems at the craek tip in austenite does not depend on the Schmid factors.

关键词： crack tip dislocation configuration Schmid factor duplex strainless steel

LOW ENERGY dislocation STRUCTURES DUE TO FATIGUE SOFTENING

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Acta Metallurgica Sinica(English Letters) 1989年第6期2卷 422-427页

作者： LAIRD Campell University of Pennsylvania U.S.A

The evolution of dislocation structures in 6% prestrained steel 1018 during fatigue has been studied by *** dislocations are quite movable,the loose cells quickly change to “checkboard”structures,in which the main cell walls lie about {100}.Then,the low energy dislocation structures *** walls and abyrinth structures are *** characteristic of labyrinth and the orientation of dipolar walls are quite similar to fcc *** indicates the energy state of system and the moving ability of dislocations are important factors affect- ing softening process,rather than the slip geometric characteristic of dislocations and details of *** decreasing in misorientation between adjoining cells and internal stress are discussed.

关键词： steel 1018 fatigue softening dislocation configuration

Investigation on Creep Mechanism of a Ni3Al-based Single Crystal Superalloy IC6SX under 760℃/540MPa

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Investigation on Creep Mechanism of a Ni3Al-based Single Cry...