检索结果-南通市图书馆

Journal of Magnesium and Alloys 2024年第4期12卷 1619-1637页

作者： Yongbiao Yang Jinxuan Guo Cuiying Wang Wenxuan Jiang Zhimin Zhang Qiang Wang Xing Zhang College of Materials Science and Engineering North University of ChinaLane 3Xueyuan RoadTaiyuanShanxi 030051China North Hongyang mechanical and electronic limited company of Henan Province China

hot torsion tests for AZ80 magnesium alloy were carried out in the temperature range of 380℃-260℃,with a constant decreasing temperature rate of 10℃/s in order to weaken the basal texture and refine the *** results indicated that the average grain sizes were refined forming gradient structure with increasing specimen radial position from center(12.2-5.4μm),and that the initial basal texture intensity of the extruded magnesium alloy was weakened from 46.2 to ***,the extension twins(ETs)could be disintegrated from the twins forming separated twins with smaller ***,ETs with the same twin variant intersecting with each other could be coalesced forming grains with similar orientation,while ETs with different twin variants were separated by twins boundaries contributing to grain ***,in addition to the conventional continuous dynamic recrystallized(CDRX)grains with 30˚orientation rotated around C-axis of the parent grains,CDRXed grains with 30˚rotation around a-axis and random rotation axis were also ***,the CDRX evolution induced twins were also elaborated,exhibiting the complex competition between CDRX and *** torsion deformation with constant decreasing temperatures rate is an effective way of grain refinement and texture modification.

关键词： Texture Microstructure hot torsion Decreasing temperature AZ80

Effect of hot torsion Parameters on Development of Ultrafine Ferrite Grains in Microalloyed Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第1期19卷 47-52页

作者： B Eghbali Department of Materials Engineering Sahand University of Technology

hot torsion testing was performed on a low carbon Nb-Ti microalloyed steel to study the effects of hot tor- sion parameters, strain and strain rate, on ultrafine ferrite grains production through dynamic strain-induced trans- formation, at a deformation temperature just above At3. The initiation and evolution of ultrafine ferrite grains were studied. The results show that the amount of strain and strain rate has conversely effect on the volume fraction and grain size of ultrafine ferrite grains. With increasing strain, the interior of austenite grains become activated as nucle- ation sites for fine ferrite grains. As a result, ferrite grains continuously nucleate not only at the former austenite grain boundaries but also inside the austenite grains which leads to a rapid increase in volume fraction of ultrafine grains. Increasing of strain rate reduces the tendency of ferrite grains coarsening so that ultrafine ferrite grains are achieved, while the volume fraction of ultrafine grains decreases at the same strain level.

关键词： dynamic strain induced transformation grain refinement ferrite hot torsion steel

Dynamic recrystallization during hot torsion of Al-4Mg alloy

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2003年第2期10卷 45-48页

作者： Junpin Lin, Yanli Wang, Zhi Lin, and Guoliang ChenState Key Laboratory of Advanced Metal Materials, University of Science and Technology Beijing, Beijing 100083, China Lab. of Adv. Metal Mat. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Binary Al-4Mg alloy have been deformed by hot torsion at 300-500 deg C andstrain rates of 0.006-1.587 s^(-1) to a true strain of 5.5. The specimens were annealed in vacuumfor 1.5 h at 500 deg C and then water quenched. The study indicates that the dynamicrecrystallization occurs during hot torsion of Al-4Mg alloy in a certain range of Z parameter(Zener-Hollmon Parameter), i.e. 19.3 <= lnZ <=24.8. Increasing the strain rate at higher deformationtemperature or reducing the strain rate at lower deformation temperature accelerates the occurrenceof dynamic recrystallization in the alloy.

关键词： Al-4Mg alloy dynamic recrystallization hot torsion

The effects of deformation parameters and cooling rates on the aging behavior of AZ80+0.4%Ce

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第2期12卷 639-658页

作者： Yongbiao Yang Jinxuan Guo Cuiying Wang Ting Yan Zhang Wenxuan Jiang Zhimin Zhang Qiang Wang Guojun Li Jun Wang College of Materials Science and Engineering North University of ChinaLane 3Xueyuan RoadTaiyuanShanxiChina030051 State Key Laboratory of Advanced Stainless Steel Materials Taiyuan Iron Steel(Group)Co.Ltd.Taiyuan 030003China Technology Center Shanxi Taigang Stainless Steel Co.Ltd.Taiyuan 030003China

The extruded AZ80+0.4%Ce magnesium alloy was twisted in the temperature range of 300-380℃by using a Gleeble 3500 thermal simulation test machine with a torsion *** deformed cylindrical specimens were cooled at a cooling rate of 10℃/s or 0.1℃/s,respectively,and aged at 170℃.The microstructure analysis results showed that the grain size decreased with increasing specimen radial position from center(SRPC),and that the strong initial basal texture of the extruded magnesium alloy was *** continuous and discontinuous dynamic recrystallization mechanisms were involved in contributing to the grain refinement for all specimens *** a novel extension twinning induced dynamic recrystallization mechanism was proposed for specimen deformed at 300℃.For the specimens deformed at 300℃and 340℃followed by a slow cooling rate(0.1℃/s),precipitates of various shapes(β-Mg_(17)Al_(12)),with the dominant precipitates being on the grains boundaries,appeared on the surface *** specimen deformed at 380℃,lamellar precipitates(LPS)in the interiors of the grains were *** aging,the LPS still dominated for specimens twisted at 380℃;however,the LPS gradually decreased with decreasing deformation temperatures from 380℃to 300℃.Dynamically precipitatedβ,especially those decorating the grain boundaries,changed the competition pictures for the LPS and precipitates of other shapes after ***,LPS dominated the areas for the center section of the specimens after aging regardless of deformation *** temperature deformation with high SRPC followed by rapid cooling rate increased the micro hardness of the alloy after aging due to refined grain,reduced precipitates size,decreased lamellar spacing as well as strain hardening.

关键词： AZ80+0.4%Ce magnesium alloy hot torsion Deformation parameters Cooling rate Aging Micro hardness

Characterization of Austenite Dynamic Recrystallization under Different Z Parameters in a Microalloyed Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第4期27卷 359-363页

作者： M.Shaban B.Eghbali Department of Materials Science and Engineering Sahand University of Technology

A low carbon Nb-Ti microalloyed steel was subjected to hot torsion testing over the temperature range 850-1100℃ and strain rates 0.01-1 s-1 to study the influence of deformation conditions on the dynamic recrystallization characteristics of austenite. The results show that dynamic recrystallization occurs more easily with the decrease of strain rate and the increase of deformation temperature. The complete dynamically recrystallized grain size as a function of Zener-Hollomon parameter was established. It was found that dynamically recrystallized grain sizes decrease with increasing strain rate and decreasing deformation temperature. The effect of microalloying elements on peak strain was investigated and the solute drag corrected peak strain was determined. Also, the dynamic recrystallization map of austenite was obtained by using recrystallization critical parameters.

关键词： Dynamic recrystallization Microalloyed steel Grain size hot torsion