检索结果-南通市图书馆

Effects of Processing Parameters on Microstructure and Properties of Ultra High Strength Linepipe Steel

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2012年第10期28卷 889-894页

作者： Xiaodan Wu Hakcheol Lee Young Min kim nack j.kim University of Pittsburgh Pittsburghl PA 15213USA Pohang University of Science and Technology Pohang 790-784Korea

To examine the effect of processing parameters on microstructural evolution and to obtain the excellent combination of strength and toughness, simulation of thermo-mechanical processing was conducted using the Gleeble machine. Trial production was then conducted under the conditions obtained by Gleeble tests. Based on the results of microstructure analysis and mechanical property evaluation, the relationship between microstructural features and mechanical properties was elucidated. The result shows that the volume fraction of constituted phases can be controlled through adjusting the cooling rate and finish cooling temperature in order to get different strength levels. As cooling rate increases, the volume fraction of upper bainite increases, which leads to the increase of strength. The upper shelf energy （USE） increases with increasing volume fraction of acicular ferrite in bainite base because of the small effective acicular ferrite grain size. Ductile-brittle transition temperature （DBTT） decreases with increasing acicular ferrite volume fraction. High reduction in the rough stage has great influence on grain refinement.

关键词： Linepipe steel Microstructure Gleeble test TMCP (thermomechanicalcontrol process)

Effect of 1Al addition on deformation behavior of Mg

在线全文

学校读者我要写书评

暂无评论

journal of Magnesium and Alloys 2021年第2期9卷 489-498页

作者： ji Hyun Hwang A.Zargaran Gyeongbae Park O.Lee B.-j.Lee nack j.kim Center for Advanced Aerospace Materials Pohang University of Science and Technology(POSTECH)PohangSouth Korea

Deformation behavior of 1 Al containing Mg alloy has been investigated in the present *** annealing,the Mg-1 Al alloy shows a typical basal *** compared to the pure Mg having a similar texture and grain size,the Mg-1 Al alloy shows much higher strength and larger *** trace analyses of the tensile strained specimens show that non-basal slips such as pyramidal I and II slips can be easily activated at an early stage of deformation in the Mg-1 Al alloy and the grains in the Mg-1 Al alloy are seen to accommodate a larger degree of deformation than those in the pure Mg at a given *** increasing tensile strain,however,there is a strain localization along the initially formed slip lines of non-basal slips,forming surface steps without activating multiple slip lines.

关键词： Deformation behavior Slip trace analysis Non-basal slip Strain localization Ductility

Effects of Cu addition on formability and surface delamination phenomenon in high-strength high-Mn steels

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2020年第8期36卷 44-51页

作者： Min Chul jo jisung Yoo Min Cheol jo Alireza Zargaran Seok Su Sohn nack j.kim Sunghak Lee Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 37673South Korea Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohang 37673South Korea Department of Materials Science and Engineering Korea UniversitySeoul 02841South Korea

The formability of austenitic high-Mn steels is a critical issue in automotive applications under nonuniformly-deformed environments caused by dynamic strain *** austenite stabilizing alloying elements in those steels,Cu has been known as an effective element to enhance tensile properties via controlling the stacking fault energy and stability of *** effects of Cu addition on formability,however,have not been sufficiently reported *** this study,the Cu addition effects on formability and surface characteristics in the austenitic high-Mn TRIP steels were analyzed in consideration of inhomogeneous microstructures containing the segregation of Mn and *** reveal determining factors,various mechanical parameters such as total elongation,post elongation,strain hardening rate,normal anisotropy,and planar anisotropy were correlated to the hole-expansion and cup-drawing test *** respect to microstructural parameters,roles of(Mn,Cu)-segregation bands and resultant Cu-rich FCC precipitates on the formability and surface delamination were also discussed.

关键词： High-Mn steel Cu effects Cu-rich FCC phase Hole-expansion test Formability Stretch-flangeablity Surface delamination

Strip Casting of High Performance Structural Alloys

在线全文

学校读者我要写书评

暂无评论

Strip Casting of High Performance Structural Alloys

轧制工艺参数对0.06C-0.31Mo微合金化高强度钢组织和性能的影响

The 8th China-Korea Workshop on Advanced Materials

作者： S S Park j G Lee nack j kim Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 790-784Korea

＜正＞ There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center’s activities in the development of high performance alloys by strip casting. Examples include （1） Al alloys, （2） wrought Mg alloys, and （3） bulk metallic glass （BMG） alloys.

关键词： strip casting 6061 Al alloy AZ Mg alloy bulk metallic glass (BMG) alloy dispersion hardening

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

特殊钢 2007年第1期28卷 29-31页

作者：吴晓丹 Hakcheol Lee Young Min kim nack j kim 太原钢铁公司太原030003 韩国浦项工业大学

用Gleeble热模拟试验机研究了0．06C-0．31Mo V—Nb-Ti—B微合金化钢再结晶区压下率（35．0％-52．0％）、非再结晶区压下率（60．2％-70．3％）、冷却速度（20—38℃／s）等轧制参数对钢的组织和机械性能的影响。试验结果表明，随着轧... 详细信息

用Gleeble热模拟试验机研究了0．06C-0．31Mo V—Nb-Ti—B微合金化钢再结晶区压下率（35．0％-52．0％）、非再结晶区压下率（60．2％-70．3％）、冷却速度（20—38℃／s）等轧制参数对钢的组织和机械性能的影响。试验结果表明，随着轧后冷却速度加大，上贝氏体的体积比增加导致钢强度的提高；贝氏体基体中针状铁紊体含量越多，上平台能（USE）越大，韧-脆转变温度越低，因此，贝氏体基体中针状铁紊体能改善管线钢的机械性能。

关键词： 0.06C-0.31Mo微合金化管线钢控制轧制组织机械性能

MICROSTRUCTURE　AND　MECHANICAL　PROPERTIES　OF　RAPIDLY　SOLIDIFIED　Al－Fe　BASED　ALLOYS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 549-553页

作者： W.j. Park S. Ahn R. Schmees and nack j. kim(1)(Center for Advaned Aerospace Materials, POSTECH. Pohang 790-784, Korea )2)(Research Institute of industrial Science & Technology, Pohang 790-600, Korea )3)(Pratt and Whitney,West Palm Beach, FL, USA ) Cent for Advanced Aerospace Materials Pohang South Korea

The effects of additions of Ti and W on microstructure and mechanical properties of rapidly solidified Al-Fe-V-Si alloys were investigated. Alloy powders were produced by the centrifugal rotary atomization process. After atomization, powders were screened to various mesh sizes to see the effect of powder size on the mechanical *** Powders were consolidated into billets using conventional powder metallurgy process, and then extruded into bar *** analysis shows that the W addition results in the heterogeneous *** the other hand, the Ti addition refines the *** containing both Ti and W has the highest thermal stability of the dispersoid. These variations in the microstructure are well reflected in the mechanical properties in that the Ti containtng alloys (with or without W) have the higher strength and ductility than the W containing alloy. It also shows that the alloys made of the coarser powders have better combinations of strength and ductility than those made of the finer powders.

关键词： rapid solidification powder metallurgy high temperature Al alLoys

在线全文

学校读者我要写书评

暂无评论

向轻金属挑战——低密度钢 008

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

中国冶金报

作者： Dong-Woo Suh nack. j. kim 张朝磊

近年来，低密度钢或者轻质钢再次激发起广泛的兴趣。据估算，钢材的密度仅需降低10%就可以保持甚至显著提高其在汽车工业中应用的优越性和竞争力。然而，汽车工业对材料的比强度、成形性和连接性能有着严格的要求。虽然与工业应用密切...

近年来，低密度钢或者轻质钢再次激发起广泛的兴趣。据估算，钢材的密度仅需降低10%就可以保持甚至显著提高其在汽车工业中应用的优越性和竞争力。然而，汽车工业对材料的比强度、成形性和连接性能有着严格的要求。虽然与工业应用密切相关，但是低密度钢的成功研制首先将强烈依

关键词：

来源： cnki报纸评论

在线全文

cnki报纸

学校读者我要写书评

暂无评论

journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.jeong S.W.Lee W.j.kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

Liquid crystal-integrated metasurfaces for an active photonic platform

在线全文

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2024年第6期7卷 5-29页

作者： Dohyun Kang Hyeonsu Heo Younghwan Yang junhwa Seong Hongyoon kim joohoon kim junsuk Rho Department of Mechanical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Electrical Engineering Pohang University of Science and Technology(POSTECH)Pohang 36763Republic of Korea POSCOPOSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics Pohang 37673Republic of Korea National Institute of Nanomaterials Technology(NINT) Pohang 37673Republic of Korea

Metasurfaces have opened the door to next-generation optical devices due to their ability to dramatically modulate electromagnetic waves at will using periodically arranged ***,metasurfaces typically have static optical responses with fixed geometries of nanostructures,which poses challenges for implementing transition to technology by replacing conventional optical *** solve this problem,liquid crystals(LCs)have been actively employed for designing tunable metasurfaces using their adjustable birefringent in real ***,we review recent studies on LCpowered tunable metasurfaces,which are categorized as wavefront tuning and spectral *** to numerous reviews on tunable metasurfaces,this review intensively explores recent development of LC-integrated *** the end of this review,we briefly introduce the latest research trends on LC-powered metasurfaces and suggest further directions for improving *** hope that this review will accelerate the development of new and innovative LC-powered devices.

关键词： tunable metasurface liquid crystal active metasurface electrically tunable optical system