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Low-Temperature Nitriding by Means of SMAT

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材料热处理学报 2004年第5期25卷 301-306页

作者： W.P.Tong H.W.Zhang N.R.Tao Z.B.Wang J.Lu K.Lu ShenyangNationalLaboratoryforMaterialsScience InstituteofMetalResearchChineseAcademyofSciencesShenyang110016China lasmis UniversityofTechnologyofTroyes10000TroyesFrance.

The microstructure in the surface layer of iron and steel samples can be refined at the nanometer scale by means of a surface mechanical attrition treatment (SMAT) that generates repetitive severe plastic deformation to the surface layer. The subsequent nitriding kinetics of the as-treated samples with the nanostructured surface layer is greatly enhanced so that the nitriding temperatures can be reduce to 300 - 400 °C regions. This enhanced processing method demonstrates both the technological significance of nanomaterials in advancing the traditional processing techniques, and provides a new approach for selective surface reactions in solids. This article reviews the present state of the art in this field. The microstructure and properties of SMAT samples nitrided will be summarized. Further considerations of the development and applications of this new technique will also be presented.

关键词：低温渗氮 SMAT 纳米结晶表面机械损耗

Gaseous Nitriding Process of Surface Nanocrystallized (SNCed) Steel

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Journal of Materials Science & Technology 2002年第6期18卷 566-568页

作者： DuohuiBEI JianLUE 等 SchoolofMaterialsScienceandEngineering ShanghaiJiaoTongUniversityShanghai200030China lasmis UniversityofTechnologyofTroyes10000TroyesFrance

The behavior of gaseous nitriding on the surface nanocrystallized (SNCed) steel was investigated. The mild steel discs were SNCed on one side by using the method of ultrasonic shot peening. The opposite side of the discs maintained the original coarse-grained condition. The gaseous nitriding was subsequently carried out at three different temperatures: 460, 500 and 560℃. The compound layer growth and diffusion behavior were then studied. It was revealed that SNC pretreatment greatly enhances both diffusion coefficient D and surface reaction rate. As a result, nitriding time could be reduced to the half. It was also found that the growth of compound layer with nitriding time conformed with parabolic relationship from the start of nitriding process in the SNCed samples.

关键词： Nitriding process Ultrasonic shot peening Surface nanocrystallization (SNC)

Mechanical and Wear Properties of Nanostructured Surface Layer in Iron Induced by Surface Mechanical Attrition Treatment

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Journal of Materials Science & Technology 2003年第6期19卷 563-566页

作者： NairongTAO WeipingTONG ZhenboWANG WeiWANG ManlingSUI JianLU KeLU ShenyangNationalLaboratoryforMaterialsScience InstituteofMetalResearchChineseAcademyofSciencesShenyang110016China lasmis UniversityofTechnologyofTroyes10000TroyesFrance

A porosity-free and contamination-free surface layer with grain sizes ranging from nanometer to micrometer in Fe samples was obtained by surface mechanical attrition treatment (SMAT) technique. Mechanical and wear properties of the surface layer in the SMATed and annealed Fe samples were measured by means of nanoindentation and nanoscratch tests, respectively. Experimental results showed that the hardness of the surface layer in the SMATed Fe sample increased evidently due to the grain refinement. The elastic moduli of the surface layers in the SMATed and annealed Fe samples were unchanged, independent of grain size in the present grain size regime. Compared with the original Fe sample, the wear resistance enhanced and the coefficient of friction decreased in the surface layer of the SMATed Fe sample.

关键词： Nanocrystallites Iron Nanoindentation Hardness Wear

Numerical Methodology for Metal Forming Processes Using Elastoplastic Model with Damage Occurrence

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Journal of Materials Science & Technology 2006年第2期22卷 279-283页

作者： A.Cherouat H.Borouchaki K.Saanouni P.Laug lasmis-CNRS FRE 2719 University of Technology of Troyes BP 2060-10010TroyesFrance lasmis-CNRS FRE 2719 University of Technology of Troyes BP 2060-10010Troyes France lasmis-CNRS FRE 2719 University of Technology of Troyes BP 2060-10010 Troyes France INRIA Rocquencourt BP 105-78153 Le ChesnayFrance

Ductile damage often occurs during metal forming processes due to the large thermo-elasto （visco） plastic flow Iocalisation. This paper presents a numerical methodology, which aims to virtually improve any metal forming processes. The methodology is based on elastoplastic constitutive equations accounting for nonlinear mixed isotropic and kinematic hardening strongly coupled with isotropic ductile damage. An adaptive remeshing scheme based on geometrical and physical error estimates including a kill element procedure is used. Some numerical results are presented to show the capability of the model to predict the damage initiation and growth during the metal forming processes.

关键词： Finite elastoplasticity Ductile damage Error estimation Adaptive remeshing Metal forming processes

Compressive behavior and energy absorption of metal porous polymer composite with interpenetrating network structure

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中国有色金属学会会刊：英文版 2006年第B2期16卷 439-443页

作者： LIU Yu GONG Xiao-lu Institut Charles Delaunay CNRS FRE 2848 LASMIS UTT 12 rue Marie Curie BP 2060 10010 Troyes France

Interpenetrating phase composites (IPCs) are a new class of composite materials with improved combinations of mechanical and physical properties. This study was performed on a new type of IPC called metal porous polymer composite (MPPC) with an interpenetrating network structure. Aluminum-polypropylene (AI-PE) and Aluminum-epoxy resin (Al-Ep) composites were produced by infiltrating the polymer in the aluminum foam. The composite microstructures were characterized using SEM observation. The compressive behavior and energy absorption characteristics of MPPC were investigated and compared with the aluminum foams. The compressive modulus of composite was compared with the VOIGT-REUSS bounds and HASHIN-SHTRIKMAN (H-S) bounds models. The experimental modulus of compressive tests falls well within the theoretical models.

关键词：金属多孔聚合物复合物互穿网络结构压缩行为能量吸收 MPPC复合物

In Situ Synthesis of Nanocrystalline Intermetallic Compound Layer during Surface Mechanical Attrition Treatment of Zirconium

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材料热处理学报 2004年第5B期25卷 1242-1246页

作者： SUNCai-yun XIEJi-jia WUXiao-lei HONGYou-shi LIUGang LUJian LUKe StateKeyLaboratoryofNonlinearMechanics InstituteofMechanicsChineseAcademyofSciencesBeijing100080People＇sRepublicofChina ShenyangNationalLaboratoryforMaterialsSciences InstituteofMetalResearchChineseAcademyofSciencesShenyang110016People＇sRepublicofChina lasmis UniversityofTechnicalofTroyes10000TroyesFrance

The surface mechanical attrition treatment (SMAT) technique was developed to synthesize a nanocrystalline (NC) layer on the surface of metallic materials for upgrading their overall properties and performance. In this paper, by means of SMAT to a pure zirconium plate at the room temperature, repetitive multidirectional peening of steel shots (composition (wt%): 1C, ***, base Fe) severely deformed the surface layer. A NC surface layer consisting of the intermetallic compound FeCr was fabricated on the surface of the zirconium. The microstructure characterization of the surface layer was performed by using X-ray diffraction analysis, optical microscopy, scanning and transmission electron microscopy observations. The NC surface layer was about 25 urn thick and consisted of the intermetallic compound FeCr with an average grain size of 25±10 nm. The deformation-induced fast diffusion of Fe and Cr from the steel shots into Zr occurred during SMAT, leading to the formation of intermetallic compound. In addition, the NC surface layer exhibited an ultrahigh nanohardness of 10.2 GPa.

关键词：金属间化合物锆合金表面机械磨损变形 SMAT 纳米结晶

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金属板材成形中拉深损伤模拟的两种求解方法

塑性工程学报 2002年第4期9卷 47-55页

作者：郭英乔 Y.M.Li K.Saanouni A.Cherouat G.Loppin K.Debray Lab.GMMS UniversityofReimsChampagneArdenne GSM/lasmis

讨论用数值模拟预测板材成形中发生拉深损伤破坏的两种不同的求解方法。第一种是采用完全耦合的弹塑性破坯模型的动力显式数值方法。基于状态参量的不可逆热力学过程 ,完全耦合的本构方程考虑各向同性强化和拉深。这些已引入有限元软件A... 详细信息

讨论用数值模拟预测板材成形中发生拉深损伤破坏的两种不同的求解方法。第一种是采用完全耦合的弹塑性破坯模型的动力显式数值方法。基于状态参量的不可逆热力学过程 ,完全耦合的本构方程考虑各向同性强化和拉深。这些已引入有限元软件ABAQUS/E用于对金属成形的模拟。在数值技术方面 ,隐式积分方法被用来对本构方程的局部时间积分 ,动力显式技术用于求解总体平衡方程。第二种方案是采用简化的损伤模型的方法 ,被称为逆法 (InveseApprch)。I.A被限定在考虑各向同性强化和损伤的塑性全量理论基础上的简单的本构关系。做比例加载和临界损伤达到以后的损伤饱和假定 ,可以得到损伤演化方程的封闭解。这两种损伤模型在编程中的实施采用两种方式 :计算中考虑或不考虑损伤作用 ,也就是耦合的或非耦合的计算。

关键词：板材成形深拉深损伤模型数值模拟

Effect of Stacking Sequences on the Mechanical and Damping Properties of Flax Glass Fiber Hybrid

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Journal of Renewable Materials 2019年第9期7卷 877-889页

作者： Khouloud Cheour Mustapha Assarar Daniel Scida Rezak Ayad Xiaolu Gong Universitéde Reims Champagne Ardenne LISM EA 469551097 ReimsFrance Universitéde Technologie de Troyes ICD/LASMISUMR CNRS 628110010 TroyesFrance

The aim of this study is to show the interest of the mechanical and dynamical properties of glass-flax hybrid ***,various staking sequences of glass-flax hybrid composites were manufactured and tested in free *** damping coefficients were identified by fitting the experimental responses of free-free bending *** obtained results show that the staking sequences and the position of flax fiber layers in the hybrid composites changed the properties,so a classification of different stacking sequences was *** fact,the hybrid laminate made of two glass external layers placed on both sides of four flax layers is very interesting in term of its mechanical and damping ***,it showed better specific bending modulus and loss factor than glass composites with proportions of 31 and 39%,respectively.A study of a structure of this composite has been made to validate the obtained results.

关键词： Flax fiber glass fiber hybrid composite damping mechanical properties

Surface Nanocrystallization (SNC) of Metallic Materials-Presentation of the Concept behind a New Approach

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Journal of Materials Science & Technology 1999年第3期15卷 193-197页

作者： Lu, K Lu, J Chinese Acad Sci Met Res Inst State Key Lab RSA Shenyang 110015 Peoples R China Univ Technol Troyes LASMIS F-10000 Troyes France

In this paper, a concept of surface nanocrystallization (SNC) of metallic materials is introduced. Three types of SNC processes are classified. Different SNC mechanisms and possible techniques for SNC are discussed with emphasis on mechanically induced surface self-nanocrystallization. Further development and prospects are addressed with respect to the properties and behaviors of the materials with a nanocrystalline surface. Enhancement of the behavior of the engineering materials by means of the SNC technology and its industrial application possibilities are analyzed.

关键词： SNC of Metallic Materials-Presentation of the Concept behind a New Approach Figure