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Microstructural evolution in electroformed nickel shaped-charge liners with nano-sized grains undergone deformation at ultrahigh strain rate

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International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 617-623页

作者： Feng Yang Chun-hua Li Sheng-wei Cheng Lei Wang Wen-huai Tian School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Nickel shaped-charge liners with nano-sized grains were prepared by the electroforming technique, and the deformation at ultrahigh strain rate was performed by explosive detonation. The as-formed and post-deformed microstructures of electroformed nickel shaped-charge liners with nano-sized grains were observed by means of transmission electron microscopy, and the orientation distribution of the grains was analyzed by the electron backscattering pattern （EBSP） technique. The melting phenomenon in the jet fragment and the recovery and recrystallization in the slug after plastic deformation at ultrahigh-strain rate were observed in the ultrafine-grained nickel shaped-charge liners. The research evidence shows that dynamic recovery and recrystallization play an important role in plastic deformation at ultrahigh strain rate.

关键词： electroformed nickel nanosized plastic deformation electroformation microtexture dynamic recovery and recrystallization

Crystal defects formed in electroformed nickel liners of shaped charges

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Acta Metallurgica Sinica(English Letters) 2009年第5期22卷 383-391页

作者： Feng YANG Wenhuai TIAN Chuanchao FENG Baosheng WANG Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China 210 Institute Beijing 100081 China

Two types of electroformed nickel liners of shaped charges were prepared by electroforming technique. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, electron backscattering diffraction （EBSD） technique and high resolution electron microscopy （HREM） have been employed to investigate the crystal defects formed in electroformed nickel liners of shaped charges. The result shows that （100） fiber texture which is parallel to the grown direction exists in the electroformed nickel prepared by using direct current electroforming without any additives, and （111） fiber texture exists in the electroformed nickel prepared by using direct current electroforming with additives. The deposits prepared by using direct current electroforming possess columnar grain with an average grain size of 30 μm in width and 170 μm in length. The deposits prepared with additives are composed of a colony structures with grain size of about 29 nm, and a lot of crystal defects such as twins, antiphase boundaries and stacking faults have been observed in the electroformed nickel.

关键词： electroformation Nickel Nanostructure Crystal defect Texture

Microstructure and penetration behavior of electroformed copper liners of shaped charges during explosive detonation deformation

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Journal of University of Science and Technology Beijing 2006年第1期13卷 73-77页

作者： Ailing Fan Wenhuai Tian Qi Sun Baoshen Wang Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China Taiyuan University of Science and Technology Taiyuan 030024 China 210 Institute Beijing 100081 China

The microstructure in the electroformed copper liners of shaped charges prepared with different electrolytes was studied by Scanning Electron Microscopy （SEM） and Electron Backscattering Kikuchi Pattern （EBSP） methods. SEM observations revealed the existence of columnar grains in electroformed copper liners of shaped charges formed by electrolyte without any additive and the average grain size is about 3 μm. When an additive is introduced to the electrolyte, the grains formed in the copper liners become equiaxed and finer. EBSP results show that the columnar grain grown during electroformation has the most preferential growth direction, whereas a micro-texture does not exit in the specimen prepared by electrolyte with the additive. Further, explosive detonation deformation experiments show that penetration depth is dramatically improved when the electroformed copper liners of shaped charges exhibit equiaxed grains.

关键词： electroformation additive microstructure explosive detonation deformation penetration

MICROSTRUCTURAL CHARACTERISTICS ASSOCIATED WITH HIGH- STRAIN-RATE PLASTIC DEFORMATION IN THE ELECTROFORMED COPPER LINER OF SHAPED CHARGES

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 620-626页

作者： A.L. Fan W.H. Tian Q. Suns B.S. Wang Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China Taiyuan University of Science and Technology Taiyuan 030024 China 210 Institute The Chinese Ordnance Industry Institute Beijing 100081 China

The microstructures of electroformed copper liners of shaped charges that had undergone high-strain-rate deformation were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Meanwhile, the orientation distribution of the grains in the recovered jet was examined by electron backscattering Kikuchi pattern （EBSP） technique. EBSP analysis reveals that the fibrous texture observed in the as-electroformed copper liners disappeared after explosive detonation deformation. OM observation shows that the microstructure evolves system- atically from the jet center to its perimeter during cooling from high temperatures after explosive detonation deformation. This microstructural characteristic is similar to that of solidification, i.e. there exist equiaxed grains in the center of the jet and significant columnar grains around the equiaxed grains. The result reveals that there is melting-related phenomenon in the jet center. Corresponding microhardness variations from the jet center to its perimeter is also determined. All the phenomena can be explained by a strong gradient of temperature across the section of the jet during plastic deformation at high-strain-rate.

关键词： jetting electroformation microstructure hardness,ultra-high strain rate deformation

Microstructure and texture of electroformed copper liners of shaped charges

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Journal of University of Science and Technology Beijing 2002年第4期9卷 265-268页

作者： WenhuaiTian HongyeGao AilingFan XiaoouShan QiSun MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China Beijing210Institute Beijing100081China

The microstructures of copper liners of shaped charges prepared byelectroforming technique were investigated by transmission electron microscopy (TEM). Meanwhile, theorientations distributing of the grains in the electroformed copper liners of shaped charges wasexamined by the electron backscattering Kikuchi pattern (EBSP) technique. TEM observations haverevealed that these electroformed copper liners of shaped charges have the grain size of about 1-3mu m and the grains have a preferential orientation distribution along the growth direction. EBSPanalysis has demonstrated that the as-formed copper liners of shaped charges exhibit amicro-texture, i.e. one type of fiber texture, and the preferred growth direction is normal to thesurface of the liners.

关键词： electroformation microstructure micro-texture transmission electronmicroscopy electron backscattering Kikuchi pattern

Dynamic recrystallization of electroformed copper liners of shaped charges in high-strain-rate plastic deformation

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Journal of University of Science and Technology Beijing 2002年第5期9卷 343-346页

作者： WenhuaiTian QiSun 等 DepartmentofMaterialsPhysicsandChemistry UniversityofScienceandTechnologyBeijingBeijing100083China Beijing210Institute Beijing100081China（Received2002－01－29）

The microstructures in the electroformed copper liners of shapedcharges after high-strain-rate plastic deformation were in-vestigated by transmission electron microscopy(TEM). Meanwhile, theorientation distribution of the grains in the recovered slug wasexamined by the electron backscattering Kikuchipattern(EBSP)technique. EBSP analysis illustrated that unlike theas-formed electro- formed copper liners of shaped charges the grainorientations in the recovered slug are distributed along randomly allthe directions after undergoing heavily strain deformation athigh-strain rate. Optical microscopy shows a typicalrecrystallization structure, and TEM exam- ination revealsdislocation cells existed in the thin foil specimen. These resultsindicate that dynamic recovery and recrystallization occur duringthis plastic deformation process, and the associated deformationtemperature is considered to be higher than 0.6 times the meltingpoint of copper.

关键词： electroformation high-strain-rate deformation dynamic recovery andrecrystallization transmission electron microscopy

PLASTIC DEFORMATION BEHAVIOR OF ELECTROFORMED COPPER LINER OF SHAPED CHARGE AT DIFFERENT STRAIN RATES

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Acta Metallurgica Sinica(English Letters) 2003年第1期16卷 72-77页

作者： H.Y.Gao W.H.Tian A.L.Fan Q.Sun Dept. of Mat. Phys. and Chem. Univ. of Sci. and Technol. Beijing Beijing 100083 China 210 Inst. Beijing 100081 China

The paper deals with different plastic deformation behavior of electroformed copper liner of shaped charge, deformed at high strain rate (about 1×107s-1) and normal strain rate (4×10-4s-1). The crystallographic orientation distribution of grains in recovered slugs which had undergone high-strain-rate plastic deformation during explosive detonation was investigated by electron backscattering Kikuchi pattern technique. Cellular structures formed by tangled dislocations and sub-grain boundaries consisting of dislocation arrays were detected in the recovered slugs. Some twins and slip dislocations were observed in specimen deformed at normal strain rate. It was found that dynamic recovery and recrystallization take place during high-strain-rate deformation due to the temperature rising, whereas the conventional slip mechanism operates during deformation at normal strain rate.

关键词： electroformation electron backscattering Kikuchi pattern cellular dislocation structure ultra-high-strain-rate deformation dynamic recovery and recrystallization