Fuxing YIN
,
Y. Ohsawa and A.Sato (National Research Institute for Metals
,
Tsukuba
,
Ibaraki 305-0047
,
Japan)K.Aawahara(B.B.Materia Co. Ltd.
,
Chiba-Shi
,
Chiba 267-0066
,
Japan)
材料科学技术（英文）
A high damping condition is easily obtained in Mn-(16~24)Cu-(4~6)Ni-2Fe (at. pct) alloys,when cooling rate is controlled after the solid solution treatment at 1173 K. It is observed that the temperature dependent changes of Iogarithmic decrement in 10 h cooled samples are sensitive to the alloy composition. As compared with water quenching treatment, controlled 10 h cooling improves TN temperature of the alloys extensively by producing a Mn-enriched matrix portion in the alloys. Calcuiations suggest that the relative decreases of Cu and Ni content in the matrix portion be dominated by the Ni content in the original alloys, and therefore, the volume fraction of the Cu, Ni-enriched precipitates is estimated to be about 20% and 10% in the 4Ni and 6Ni alloys, respectively. As a result, the TN temperature fOr each alloy, corresponding to the rising temperature of logarithmic decrement, has been related to the Cu, and Ni content in the Mnenriched matrix. The existence of {110} twinning boundaries is confirmed in the microstructure of both 4Ni and 6Ni alloys. However, the relative lattice strains, which the twinning boundaries act to accommodate, are found largely different in the two alloys. It is considered that boundaries with smaller orientation deviation could coordinate the external Stresses easily by cyclic moving, and therefore, the broader damping peak which occurs in the 10 h cooled 6Ni alloy becomes feasible. Electron diffraction results also indicate possible for mation of many sub-crystals in the matrix phase, which are relatively rotated on some invariant planes. Those sub-crystal boundaries might play some attenuation roles in the temperature range between TN and room temperature.
关键词:
贾飞
,
岳柯
,
涂小林
,
杨彦云
,
张宏斌
,
徐瑚珊
,
李君清
原子核物理评论
doi:10.3969/j.issn.1007-4627.2007.03.005
考虑角动量相关性的情况下计算了超重核259Db的裂变位垒Bf.计算了258Rf,259Db,266Hs和267Mt 4个超重核单中子蒸发的存活概率Wsur及其随角动量分波的变化关系.给出了中子蒸发宽度、裂变宽度和超重核蒸发一个中子的概率对激发能与角动量分波的依赖关系.
关键词:
超重元素
,
存活概率
,
裂变位垒
,
中子蒸发宽度
,
裂变宽度
王骏
,
张蓉蓉
,
刘玉柱
,
张冰
量子电子学报
doi:10.3969/j.issn.1007-5461.2009.03.001
利用离子速度成像方法对碘代直链烷烃和环烷烃分子在267 nm下的光解断键机理进行了研究.实验分析了激发态I*(5p2P1/2)和基态I(5p2P3/2)的离子影像,得到其对应速度、角度分布的各向异性参数β值和相对量子产率Φ(I)和Φ(I*).实验发现碘代直链烷烃和环烷烃分子在吸收一个267nm的光子后,都发生快速的C-I断键,直接解离生成激发态I*和基态I原子.与碘代直链烷烃相比,碘代环烷烃分子具有明显不同的角度分布特征,碘代环烷烃分子基态的β值大于激发态.并且随着α碳原子上所取代的烷基变重,Φ(I*)有变小的趋势.
关键词:
光解动力学
,
碘代烷烃
,
离子速度成像
,
共振增强多光子电离
,
相对量子产率
Journal of Applied Physics
We report bulk metallic glasses with critical diameter (D(c)) in the 20-27 mm range over a relatively wide composition range in the Mg-Cu-Ag-Gd quaternary system. Such an extraordinary glass-forming ability is correlated with the relatively strong liquid behavior of these alloys in terms of Angell's [Science 267, 1924 (1995)] fragility concept. The relaxation time of the ternary Mg(61)Cu(28)Gd(11) and quaternary Mg(59.5)Cu(22.9)Ag(6.6)Gd(11) alloys was measured. In terms of the fragility parameter D(*), the Mg(59.5)Cu(22.9)Ag(6.6)Gd(11) alloy with a critical diameter of 27 mm under copper mold casting has a D(*) of 25, higher than all the bulk metallic glass-forming alloys reported so far. The implications of these findings are discussed. (c) 2007 American Institute of Physics.
关键词:
bulk-metallic-glass;medium-range order;mg-cu-y;supercooled liquids;thermal-stability;viscous-flow;cooling rate;crystallization;viscosity;temperature
吴良芹
材料科学与工程学报
对60Si2Mn钢CCT曲线进行测定,研究了60Si2Mn钢不同冷速下的组织变化及热处理后的组织性能.结果表明,60Si2Mn钢的临界冷却速度在3～5℃/s之间,Ms点267℃,具有很高的淬透性,经3min水淬+自回火后,从心部至表面的硬度分布均匀,均在44.67HRC以上,冲击吸收能量在13.12J以上,热处理后的60Si2Mn钢具有高的硬度和良好的韧性,能够满足高性能材料的要求.
关键词:
60Si2Mn钢
,
CCT曲线
,
金相组织
,
组织性能
,
马氏体
梁文涛
,
吕柳
,
公茂刚
,
吕海飞
,
许小亮
功能材料
研究了不同壳层厚度(0～5.5ML)的CdSe/CdS核壳量子点的一次和高次拉曼散射,具体分析了CdSe和CdS的表面模随着壳层厚度的变化情况.结果表明,随着壳层厚度的增加,CdSe表面模(SO1)从198cm-1频移到185cm-1,CdS的表面模(SO2)从275cm-1频移到267cm-1,并且SO1和SO2试验结果与由介电连续模型得到的理论值很接近.此外,根据CdSe表面模的频移,对随着CdS壳层厚度的增加而引起的核层(CdSe)的介电常数随环境的变化做出了修正.
关键词:
CdSe/CdS
,
拉曼
,
表面模
黄刚
,
吴开明
,
周峰
,
周春泉
,
周明伟
,
焦国华
材料工程
doi:10.3969/j.issn.1001-4381.2012.04.011
利用Formaster热膨胀仪和金相法,测定了薄板坯连铸连轧工艺(CSP)生产的高碳高强度65Mn钢的CCT曲线,测得临界点为Ac1=719℃,Ac3=747℃,M.=267℃,临界冷却速率为35℃/s.使用扫描电镜和硬度仪分析表明,薄板坯连铸连轧工艺生产的65Mn钢的淬火组织细小均匀,硬度高,比传统工艺生产的65Mn钢的淬透性好.
关键词:
薄板坯连铸连轧
,
CSP
,
CCT曲线
,
淬透性
张迈生
,
王立格
,
杨燕生
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2000.02.005
本文首次采用微波辐射法(MicrowaveRadiationMethod,简称MRM)快速合成了以SrS为基质、Cu+、Bi3+为共激活剂的长余辉蓝绿色光致发光磷光体,其激发和发射主峰波长分别为267和521nm,长余辉时间约为0.5h.系统考察了在单掺杂和双掺杂情况下的发光规律,发现Bi3+与Cu+之间存在着能量传递作用,且Bi3+对Cu+具有很强的敏化和猝灭效应.
关键词:
微波辐射
,
铜
,
铋
,
硫化锶
,
长余辉
