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INFLUENCE OF STRESS STATE IN EARING PREDICTION (Ⅱ) CRYSTALLOGRAPHIC ANALYSIS OF bcc metals

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中国有色金属学会会刊:英文版 1997年第2期7卷 109-113页

作者： Li Saiyi Zhang Xinming Li Luoxing Department of Materials Science and Engineering Central South University of TechnologyChangsha 410083 Changsha Research Institute of Mining and Metallurgy Changsha 410082

The influence of stress state on earing behavior in cup drawing of bcc metals is analyzed by use of the modified Tucker method. The results show that, this influence varies with orientations, and that the earing beha... 详细信息

关键词： bcc metals earing texture cup-drawing slip mode

Review on ω Phase in Body-Centered Cubic metals and Alloys

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 1-11页

作者： Dehai Ping National Institute for Materials Science Sengen 1-2-1Tsukuba 305-0047Japan

An ω phase with a primitive hexagonal crystal structure has been found to be a ωmmon metastable phase in body-centered cubic （bcc） metals and alloys. In general, ω phase precipitates out as a high density of nanoscale particles and can obviously strengthen the alloys; however, ωarsening of the ω particles significantly reduces the alloy ductility. The ω phase has ωherent interfacial structure with its bcc matrix phase, and its lattice parameters are aω ---- x/2 x abcc and ωbcc= v/3/2 abcc abet. The ωmmon { 112} （111）-type twinning in bcc metals and alloys can be treated as the product of the ω ~ bcc phase transition, also known as the ω-lattice mechanism. The ω phase＇s behavior in metastable 13-type Ti alloys will be briefly reviewed first since the ω phase was first found in the alloy system, and then the existence of the ω phase in carbon steels will be discussed. Carbon plays a crucial role in promoting the ω formation in steel, and the ω phase can form a solid solution with various carbon ωntents. Hence, the martensitic substructure can be treated as an ct-Fe matrix embedded with a high density of nanoscale ω-Fe particles enriched with carbon. The reωgnition of the ω phase in steel is expected to advance the understanding of the relationship between the microstructure and mechanical properties in bcc steels, as well as the behavior of martensitic transformations, twinning formation, and martensitic substructure.

关键词： ω phase Martensitic steel Microstructure Microanalysis bcc metals Alloys Twinning

Slip Model Used for Prediction of r Value of bcc Metal Sheets from ODF Coefficients

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Journal of Iron and Steel Research(International) 2000年第1期7卷 36-38页

作者： PAN Hao WANG Xiao-ming Central Iron &.Steel Research Institute

Different slip models were used for prediction of r value of bcc metal sheets from ODF coefficients.According to the maximum plastic work theory developed by Bishop and Hill,it is expected that the higher of Taylor factors given by a slip’ model,the better prediction obtained based on the model.From this point of view,a composed slip model of bcc metals was presented.Based on the model,the agreement of predicted r values for deep drawing steels with experimental ones is excellent.

关键词： bcc metals r values slip model texture

Dependence of stresses on grain orientations in bcc polycrystalline films on substrates

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Chinese Physics B 2005年第9期14卷 1862-1865页

作者：张建民张研徐可为 College of Physics and Information Technology Shaanxi Normal University Xian 710062 China State Key Laboratory for Mechanical Behavior of Materials Xian Jiaotong University Xian 710049 China

Most thin films have different thermal expansion coefficients from their substrates, thus thermal stresses will be introduced into the films when the temperature is changed during annealing and service. Calculations of these stresses for grains in various crystallographic orientations have been made for seven bcc transition metals Cr, Fe, Mo, Nb, Ta, V and W. Neglecting W, which is isotropic and the stresses are equiaxial and without grain orientation （hkl） dependence, the bcc metals may be grouped into two classes. In the first class （Cr, Mo, Nb and V）, the （100）-oriented grains have the largest stresses, while the stresses σ1 and σ2 in other （hkl）-oriented grains decrease linearly with the increase of the angle between （hkl） and （100）, and with σ1 〈 σ2 except in （100）- and （lll）-oriented grains. In the second class （Fe and Ta）, on the contrary, the （100）-oriented grains have the lowest stresses, and the stresses σ1 and σ2 in other （hkl）-oriented grains increase linearly with the increase of the angle between （hkl） and （100）, and with σ1 〉 σ2 except in （100）- and （111）-oriented grains.

关键词： bcc metals stresses grain orientations calculation

Mobility of screw dislocations in bcc crystals: A review on modelling methods

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Progress in Natural Science:Materials International 2000年第10期 3-11页

作者：颜庆云 China Department of Mechanical Engineering The University of Hong Kong

This article reviews the methods employed in modelling the various aspects of mobility of screw dislocations in the body-centred cubic (bcc) structure. The behaviour of straight dislocation cores at 0 K has been well-understood following the application of traditional 2-D atomistic simulation in the past few decades. Kink-pair activation at . non-zero temperatures has been classically treated by Volterra-type line tension models, but these have been superseded in recent years by a semi-continuum approach based on the Peierls-Nabarro framework. The use of 3-D atomistic simulation techniques in studying kink-pair related problems is also emerging. There is now the prospect that engineering-oriented phenomena such as brittle-to-ductile transition and the strain-rate sensitivity of deformation textures in bcc metals can be investigated at a more fundamental level involving dislocation core behaviour.

关键词： dislocations bcc metals mechanical properties simulations.