材料期刊网

EFFECTS OF DEFORMATION ON MICROSTRUCTURE AND σ-PHASE FORMATION IN Cr_(25)Ni_(20) STAINLESS STEEL

GAO Yan LI Dejun CAO Zhiben Dalian University of Science and Technology , Dalian , Liaoning , China LI Dejun , Lecturer , Department of Materials Engineering , Dalian University of Science and Technology , Dalian , Liaoning , China

金属学报(英文版)

The microstructure of Cr_(25)Ni_(20)stainless steel under plastic deformation up to 50% has re- vealed an even distributed twins,micro-twins and deformation bands.The σ-phase formation in 800℃ aged specimens is accelerated by its nucleation at either deformation twins or recrystallized grain boundaries under less or more deformation respectively.In the recrystallized zone,the recrystallization is prior to the precipitation of σ-phase.Although recrystallization may accelerate the formation of σ-phase,it is not essential.The twins and micro-twins produced by deformation may also provide the additional nucleation sites.

关键词: plastic deformation , null , null

PREFERRED ORIENTATION OF DEPOSITED TiC COATING ON STEEL BY CVD

GUO Chengyan Jilin Institute of Technology , Changchun , ChinaGOTO Takashi HIRAI Toshio Tohoku University , Japan Associate Professor , Department of Materials Engineering , Jilin Institute of Technology , Changchun 130012 , China

金属学报(英文版)

Investigation was made of the deposited rate,surface morphology and crystal pre- ferred orientation of the dense TiC coating onto austenitic stainless steel in relation with CH_4/TiCl_4 mole ratio and temperature adopted in CVD processing. When the CH_4/TiCl_4 ratio is low or high,the preferred orientation may be(220)or(200),respec- tively,which is mainly dependent on the equilibrium concentration of active C in vapour phase.

关键词: preferred orientation , null , null

ATOMIC DIFFUSION CONTROL DURING TEMPERING OF STEEL 20Cr11MoVNbNB

FU Changpu HAN Yong Shaanxi Mechanical Engineering Institute , Xi'an , China FU Changpu , associate professor , Department of Materials Engineering , Shaanxi Mechanical Engineering Institute , Xi'an 710048 , China

金属学报(英文版)

Studies were made of the effect of tempering at temperatures from 25 to 750℃ for 0.5 to 100 h on changes of hardness,precipitated phase and its alloying element content as well as activation energy of tempering for quenched steel 20Cr11MoVNbNB.Tempering of the steel at temperatures below 400℃ may be controlled by the diffusion of C atoms in α-Fe,and above 400℃,by diffusion of Cr,also Mo or V,in α-Fe.

关键词: steel 20Cr11MoVNbNB , null , null , null

FATIGUE BEHAVIOUR OF M/B DUPLEX STRUCTURE IN A HIGH CARBON Cr-Mo-W STEEL

TIAN Baohong ZHENG Shi'an WU Lei Luoyang Institute of Technology , Luoyang , China ZHENG Shi'an , associate professor , Department of Materials Engineering , Luoyang Institute of Technology , Luoyang 471039 , China

金属学报(英文版)

Determination was carried out of fatigue crack propagation rate of steel 65Cr5Mo3W2VSiTi (LM2)with various bainite contents and M/B duplex structure tempered at various tempera- tures.The threshold value of fatigue for each processing was estimated by experimental data. The mechanism for fatigue crack propagation of M/B duplex structure in steel LM2 seems to be non-continuous.The calculated fatigue crack micro-propagation rates are found to agree with the experimental data.

关键词: duplex structure , null , null , null

Department of Metallurgy and Materials Engineering of Chongqing University

YAN Guangting Chongqing University , Sichuan , China.

材料科学技术（英文）

关键词:

Service Performance of Engineering Materials

Andrej Atrens

材料科学技术（英文）

Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.

关键词: Stress corrosion cracking , null , null

Biomimicry of bamboo bast fiber with engineering composite materials

Materials Science & Engineering C-Biomimetic Materials Sensors and Systems

Bamboo, one of the strongest natural structural composite materials, has many distinguishing features. It has been found that its reinforcement unit, hollow, multilayered and spirally-wound bast fiber, plays an extremely important role in its mechanical behavior. In the present work, on the basis of the study on bamboo bast fiber and wood tracheid, a biomimetic model of the reinforcing element, composed of two layers of helically wound fiber, was suggested. To detect the structural characteristics of such a microstructure, four types of macro fiber specimens made of engineering composites were employed: axially aligned solid and hollow cylinders, and single- and double-helical hollow cylinders. These specimens were subjected to several possible loadings, and the experimental results reveal that only the double-helical structural unit possesses the optimum comprehensive mechanical properties. An interlaminar transition zone model imitating bamboo bast fiber was proposed and was verified by engineering composite materials. In our work, the transition zone can increase the interlaminar shear strength of the composite materials by about 15%. These biomimetic structural models can be applied in the design and manufacture of engineering composite materials.

关键词: bamboo;bast fiber;biomimetics;engineering composites

GRAIN BOUNDARY FEATURE AND CREEP BEHAVIOR OF Fe-15Cr-25Ni ALLOYS

ZHANG Junshan CHEN Weixing CAO Zhiben Dalian University of Technology , Dalian , China Associate Professor , Department of Materials Engineering , Dalian University of Technology , Dalian , China

金属学报(英文版)

Creep behavior of Fe-15Cr-25Ni alloys with different grain boundary features has been in- vestigated at 850 and 950℃ and in stress range of 14.7～78.5 MPa.The single phase alloy exhibits typical recovery creep characteristics,and for the alloy in which M_(23)C_6 carbides densely precipitate at grain boundaries,the creep rate dramatically decreases and creep behav- ior is also significantly different from the single phase alloy.When the carbides precipitate at grain boundaries,the dislocation density are higher and the size of subgrains near grain boundaries are smaller than those of single phase alloy.The creep mechanisms for two grain boundary features have been discussed.

关键词: grain boundary feature , null , null

Strengthening Materials by Engineering Coherent Internal Boundaries at the Nanoscale

Science

Strengthening materials traditionally involves the controlled creation of internal defects and boundaries so as to obstruct dislocation motion. Such strategies invariably compromise ductility, the ability of the material to deform, stretch, or change shape permanently without breaking. Here, we outline an approach to optimize strength and ductility by identifying three essential structural characteristics for boundaries: coherency with surrounding matrix, thermal and mechanical stability, and smallest feature size finer than 100 nanometers. We assess current understanding of strengthening and propose a methodology for engineering coherent, nanoscale internal boundaries, specifically those involving nanoscale twin boundaries. Additionally, we discuss perspectives on strengthening and preserving ductility, along with potential applications for improving failure tolerance, electrical conductivity, and resistance to electromigration.

关键词: strain-rate sensitivity;stacking-fault energy;nano-scale twins;cu-al;alloys;nanocrystalline metals;mechanical-properties;activation;volume;copper;deformation;behavior

STATISTICAL EVALUATION OF CRITICAL INCLUSION FACTOR FOR SECONDARY RECRYSTALLIZATON IN 3%Si STEEL Lecturer,Department of Materials Engineering,Southwestern Jiaotong University,Chengdu 610031,China

LI Shuchen Southwestern Jiaotong University , Chengdu , ChinaCHEN Mengzhe KE Jun University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

On the basis of statistical data of MnS in the conventional 3% Si steel sheeets after various annealing processes,the critical inclusion factor has been evaluated to be 20 mm~(-1).The inhi- bition of MnS to grain growth has been exactly described.

关键词: 3%Si steel , null , null