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Evaluation of Stored Energy from Microstructure of Multi-component Nanostructured Cu

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Journal of Materials Science & Technology 2012年第4期28卷 289-293页

作者： Feng Yan hongwang zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

A polycrystalline Cu of 99.995% purity has been deformed by dynamic plastic deformation at liquid nitrogen temperature to a strain of 2.1 （LNT-DPD Cu）. Three distinct regions that are dominated by dislocation slip, shear banding and nanotwinning, form a multi-component nanostructure. The microstructure of each region has been quantified by transmission electron microscopy assisted by Kikuchi line analysis. Based on the structural parameters the stored energy of each region was evaluated, and the total energy can be assumed to be a linear additivity of that in each region weighted by the respective volume fraction. A microstructure based evaluation of the stored energy of multi-component nanostructure has been proposed.

关键词： Stored energy Cu Dynamic plastic deformation Transmission electron microscopy

On the microstructural evolution pattern toward nano-scale of an AISI 304 stainless steel during high strain rate surface deformation

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Journal of Materials Science & Technology 2020年第9期44卷 148-159页

作者： hongwang zhang Yiming Zhao Yuhui Wang Chunling zhang Yan Peng National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China National Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

In the present investigation,an austenitic AISI 304 stainless steel was subjected to high strain rate surface deformation by Pipe Inner-Surface Grinding(PISG)*** depth-dependent deformation parameters(strain,strain rate and strain gradient)were evaluated and the microstructures were systematically *** evolution from millimeter-to nano-scale was explored,with special attention paid to the localized *** evolution begins with the formation of planar dislocation arrays and the twin-matrix lamellae,which is followed by the localized deformation characterized by the initiation and the development of shear bands.A twinning-dominated process that was supplemented with dislocation slip-dominated one governed the microstructural evolution inside shear *** twin-matrix lamellae transform into extended/lamellar structure and finally the nanosized *** grains were substantially refined and martensitic transformation was effectively suppressed,of which the underlying mechanisms were analyzed.

关键词： Microstructural evolution Plastic deformation AISI 304 stainless steel Pipe inner-surface grinding Shear band

Fabrication of nanostructure in inner-surface of AISI 304 stainless steel pipe with surface plastic deformation

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Journal of Materials Science & Technology 2018年第11期34卷 2125-2130页

作者： hongwang zhang Yiming Zhao Yuhui Wang Huaxin Yu Chunling zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan University National Key Laboratory of Metastable Materials Science and Technology Yanshan University

In the present investigation, a pipe inner-surface grinding（PISG） technique was developed to fabricate nanostructure in the inner-surface of an austenitic 304 stainless steel pipe. PISG was performed by high speed shearing with hard sphere tips, leading to gradient distribution of strain, strain rate and strain gradient along depth. Nano-austenite with an average boundary spacing of 20 nm was generated, followed by deformation microstructure characterized by shear bands, multi-and uni-directional twins and planar dislocation arrays. Deformation induced grain refinement of austenitic 304 stainless steel with low stacking fault energy（SFE） covering 4–5 order＇s magnitude of length scales toward nanometer regime was unified.

关键词： Nanostrucutre Pipe inner-surface grinding Stainless steel Plastic deformation Nano-austenite

Twinned Martensitic Substructure in a Water Quenched Fe–1.0 wt%C Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第7期35卷 1157-1163页

作者： Haidong Sun Zuohua Wang Shuai zhang Ning Liu Pinwen Zhu Dongli Yu hongwang zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Superhard Materials College of PhysicsJilin UniversityChangchun 130012China Liren College of Yanshan University Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

A Fe–1.0 wt%C alloy was quenched into water from 1100 ℃,leading to lath martensite and plate martensite of body-centered tetragonal *** these two martensites have the twinned substructure that generates mirror symmetric diff raction patterns with extra diff raction spots around n/3(112).The twinned substructure has the origin from twinned martensitic variants,namely twin-related crystals separated by{110},rather than{112}deformation *** eff ect on the electron double diff raction of twinned variants was discussed.

关键词： Twinned martensitic substructure Twinned variant Lath martensite Plate martensite

{112}<111>Twins or Twinned Variants Induced by Martensitic Transformation?

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Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 133-140页

作者： Zuohua Wang Haidong Sun Peng Wang Ning Liu Pinwen Zhu Dongli Yu hongwang zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Liren College of Yanshan University Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Superhard Materials College of PhysicsJilin UniversityChangchun 130012China

Twinned substructure in lath martensite was induced in the interstitial free(IF)steel via a high pressure thermal cycle(heating up to 1100℃and holding for 30 min,cooling at 10℃/s to room temperature under a pressure of 4 GPa).Experimental observations and theoretical simulation confrm that the twinned substructure has the origin related to the twinned variants rather than the bcc{112}twins,while extra difraction spots were caused by crystal overlapping rather than any extra *** diferences in crystallography and electron difraction behavior between twinned variants and{112}twins were discussed in detail.

关键词： Twinned variants {112}twins Martensitic transformation Crystal overlapping Electron difraction

Origin and the Hardening Mechanism of Twinned Lenticular Martensite in a Fe-33Ni Alloy

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Acta Metallurgica Sinica(English Letters) 2023年第6期36卷 899-905页

作者： Yong Li Zuohua Wang Lihua Qian Jian Zhao Wu zhang Ping Wei hongwang zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China School of Physics Huazhong University of Science and TechnologyWuhan 430074China China Copper Huazhong Copper Cooperation Limited Huangshi 435004China College of Weaponry Engineering Naval University of EngineeringWuhan 430033China

The twinned substructure of lenticular martensite in a quenched Fe–33Ni alloy was *** contrary to the traditional viewpoint that the twinned laths come from{112}deformation twins and show insignificant hardening,we demonstrate that they are actually originated from the twinned Kurdjumov Sachs(KS)variants and can give rise to 3–4 times hardening up to~420 HV(~130 HV for the starting sample).The underlying mechanisms responsible for the propensity for twinned variants and the carbon-independent hardening for Fe–Ni system were discussed.

关键词： Twinned variants Midrib Lenticular martensite Hardening mechanism Fe-33Ni

Tempering mechanism of lath martensite induced in IF steel under high pressure

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Journal of Materials Science & Technology 2023年第29期160卷 148-160页

作者： Zuohua Wang Haidong Sun Xiaogang Guo Peng Wang Ning Liu Dongli Yu hongwang zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Liren College of Yanshan University Yanshan UniversityQinhuangdao 066004China

In this paper,low-and high-strength lath martensite(350 and 640 HV)was fabricated in an IF steel via high pressure martensitic *** microstructure and the softening during their tempering from 200°C to 800°C for 1 h were systematically investigated.A carbon-irrelevant tempering process was proposed,exhibiting a three-stage structural evolution pattern depending upon the tempering de-gree(1-(HV-HV FP)/(HV NP-HV FP),where the HV is the instant hardness,HV NP is the non-tempered hard-ness and HV FP is the fully tempered hardness):(1)low tempered(50%),clearing up the remained variant laths via the migration of the triple ***-type microstructure is tailored by low-index lamellar variant boundaries and is thus intrinsically thermally stable,whereas the mobile terminal tips decrease the tempering *** underlying mechanism for such carbon-irrelevant process was discussed and the potential effect on the tempering behavior of carbon-contained martensite was highlighted.

关键词： Tempering mechanism Lath martensite IF steel Terminal tip migration High pressure

Synthesis of Monodisperse CdS Nanorods Catalyzed by Au Nanoparticles

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Nano Research 2008年第4期1卷 314-320页

作者： hongwang zhang Savas Delikanli Yueling Qin Shuli He Mark Swihart Hao Zeng Department of Chemical and Biological Engineering University at BuffaloSUNYBuffaloNY 14260USA Department of Physics University at BuffaloSUNYBuffaloNY 14260USA Department of Physics Capital Normal UniversityBeijing 100048China

Semiconductor nanocrystals(dots,rods,wires,etc.)exhibit a wide range of electrical and optical properties that differ from those of the corresponding bulk *** properties depend on both nanocrystal size and *** with nanodots,nanorods have an additional degree of freedom,the length or aspect ratio,and reduced symmetry,which leads to anisotropic *** this paper,we report the Au nanoparticle-catalyzed colloidal synthesis of monodisperse CdS *** on systematic high resolution transmission electron microscopy studies,we propose a growth mechanism for these nanorods.

关键词： Nanorods monodisperse catalytic growth solution phase synthesis

Strain gradient induced grain refinement far below the size limit in a low carbon hypoeutectoid steel(0.19 wt%C)via pipe inner surface grinding treatment

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Journal of Materials Science & Technology 2021年第19期78卷 155-169页

作者： Wenqiang Li Yiming Zhao Ning Liu Changji Li Ruiming Ren Dayong Cai hongwang zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China National Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Liren College of Yanshan University Yanshan UniversityQinhuangdao 066004China School of Materials Science&Engineering Dalian Jiaotong UniversityDalian 116028China Qinhuangdao Vocational and Technical College Qinhuangdao 066100China

A low carbon hypoeutectoid steel(0.19 wt%C)with proeutectoid ferrite and pearlite dual-components was subjected to surface plastic deformation via pipe inner surface grinding(PISG)at room *** deformation microstructures for each component were systematically characterized along depth,and the patterns of structural evolution toward nanometer regime as well as the governing parameters were *** ferrite grains were refined down to 17 nm,and the pattern covering a length scale of 4–5 orders of magnitude from micron-to nanometer-scale follows:formation of cellular dislocation structure(CDS),elongated dislocation structure(EDS),ultrafine lamellar structure(UFL)and finally the nanolaminated structure(NL).The pearlite experiences the deformation and refinement,and finally the transforming the ultrafine pearlite(UFP)into nanolaminated pearlite(NLP)with the ferrite lamellae as thin as 20 *** for both UFL(UFP)and NL(NLP)can be realized via forming novel extended boundaries within ferrite lamellae.A critical lattice curvature of~2.8°is required for forming such extended boundary,corresponding to a minimum strain gradient of 0.25μm^(-1)for a 100 nm-thick *** below size limit(expressed by lamellar thickness d_Tin nm)is correlated with the strain gradient(χ,inμm^(-1))by:d_T=12.5/*** contributions from strain gradient caused by PISG processing and material heterogeneity were discussed.

关键词： Strain gradient Grain refinement Size limit Low carbon hypoeutectoid steel Pipe inner surface grinding