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"高温大变形+超快冷"工艺在管线钢生产中的应用肖宝亮1,许云波1,张福生2,侯晓英1,王国栋2(1.辽宁省沈阳市东北大学轧制技术及连轧自动化国家重点实验室2.沈阳铸锻工业有限公司,辽宁沈阳 110142)摘 要:通过热模拟和实验室热轧试验,研究了"高温大变形+超快速冷却"工艺和传统TMCP工艺下试验钢显微组织的区别和强韧性规律.结果表明,超高冷却速率使过冷度变大,形核率升高,新相形核主要以晶内形核为主."高温大变形+超快速冷却"工艺得到的细化针状铁素体,高密度位错以及弥散细小的析出物保证了材料的综合性能,使热轧......
基于改进CA方法的压铸镁合金微观组织模拟吴孟武1,熊守美1(1.北京市清华大学机械工程系汽车安全与节能国家重点实验室)摘 要:针对具有快速凝固特征的压铸工艺,通过热传导反算法得到较准确的压铸温度场,分析压铸镁合金凝固过程冷却曲线,建立了形核密度随冷却速率变化的形核模型.采用改进CA方法,建立了适用于镁合金hcp结构的枝晶生长模型.模型考虑了溶质扩散,成分过冷,曲率过冷以及界面各向异性等重要因素,实现了镁合金不同角度枝晶生长,再现了枝晶二次及三次枝晶臂生长,定向凝固不同温度梯度及凝固速率下的枝晶竞争生长以及三维枝......
is 4 times lower than that of Al-0.30Zr-0.03Y. Al-0.30Zr-0.03Y shows higher nucleation density, smaller precipitate radius and slower coarsening rate. The recrystallization temperature of Al-0.30Zr-0.03Y reaches 500 ℃, which is 125 and 75 ℃ higher than those of Al-0.3Zr and Al-0.3Zr-0.08Y, respectively. Key words: Al3(Zr,Y); precipitation mechanism; nucleation density; coarsening resistance......
Application of fuzzy theory on earthquake damage rate estimation of buildingsSHAO Yang-wei(邵扬威)1, WU Yu-shiang(吴玉祥)2, KAO Shih-feng(高士峰)1, HUANG Chi-jan(黄麒然)1, CHANG Kuan-yung(张宽勇)3(1. Graduate... damage-rate estimation model. The building damage survey data were recorded and constructed into files by the Architecture and Building Research Institute (ABRI), Taiwan for the 1999 Chi-Chi......
单晶Cu纳米杆拉伸力学特性的尺寸依赖性模拟白清顺1,童振1,梁迎春1,陈家轩1,王治国1(1.黑龙江省哈尔滨市哈尔滨工业大学机电工程学院)摘 要:对圆形,方形截面形状的单晶Cu纳米杆拉伸变形过程进行了分子动力学模拟.通过中心对称参数方法并结合位错形核理论分析了截面形状,截面面积和长细比对纳米杆拉伸力学特性的影响,研究了单晶Cu纳米杆拉伸力学特性的尺寸依赖性.结果表明:首次屈服后,纳米杆在"位错形核-位错延伸与滑移-晶格原子交叉滑移"的交替循环作用机制下,产生塑性变形;截面形状对纳米杆拉伸变形的初始塑性影响较小,......
, the nucleation rate is high and the fine structure of(γ+γ’) is formed at the initial precipitation stage. The γ and γ’in(γ+γ’) tend to grow into a lamellar structure because it is difficult for them to nucleate...Transformation Mechanism of (γ+γ’) and the Effect of Cooling Rate on the Final Solidification of U720Li AlloyGuang-Di Zhao1,2,Guo-Liang Yang1,Fang Liu1,Xin Xin1,Wen-Ru Sun11. Institute of Metal......
J. Cent. South Univ. Technol. (2008) 15: 218-223 DOI: 10.1007/s11771-008-0042-7 Relationship between diameter of split Hopkinson pressure bar and minimum loading rate under rock failure LI Xi...; Abstract: In order to investigate the relationship between bar diameter and loading rate of the split Hopkinson pressure bar(SHPB) setup under......
precipitates as the heterogeneous nucleation sites for primary α-Mg phases. Microscopic analysis for the location of the Al8(Mn, Fe)5 precipitate explains that the Al8(Mn, Fe)5 precipitate is the effective heterogeneous nucleation site for the primary α-Mg phase. It was also observed that increase of the Mn content in the melt and the cooling rate below to the solid/liquid two-phase region resulted......
the heterogeneous nucleation rate in the alloy melt and produce more primary non-dendritic microstructure, meanwhile, the high cooling rate also reduce the time to reach the set melt temperatures, which had... rate and cooling rate. When the stirring rate and cooling rate were low, the incubation time for the formation of non-dendritic microstructures decreased obviously with the increase of the melt......
Nucleation and crystallization of tailing-based glass-ceramics by microwave heatingBao-wei Li1,2,Hong-xia Li1,Xue-feng Zhang3,Xiao-lin Jia4,Zhi-chao Sun31. School of Materials and Engineering, Inner...">The effect of microwave radiation on the nucleation and crystallization of tailing-based glass-ceramics was investigated using a 2.45 GHz multimode microwave cavity. Tailing-based glass samples were prepared......