ZHU Kai University of Science and Technology of China
,
Hefei
,
China WANG Chongyu Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China Central Iron and Steel Research Institute
,
No.13
,
Taipingzhuang
,
Beijing
,
China
金属学报(英文版)
The calculation of electronic structure of γ'-Ni_3Al phase with or without Mg and W by the Recursion and LCAO methods clarified that Mg and W atoms lose their outer electrons par- tially after they entered γ'-Ni_3Al.It causes the reduction of the radii of the atoms.So it is preferable for Mg atom to enter γ'-phase by the substitution.The interaction between Mg and γ'-phase matrix may be strengthened and a more stable structure of γ'-phase may be formed while Mg and W entered γ'-Ni_3Al simultaneously.
关键词:
superalloy
,
null
,
null
,
null
Physica Status Solidi B-Basic Research
The electronic structure of the 13-atom Rh cluster is studied with the structure model optimized by Estiu and Zerner using the discrete variational local-spin density-functional method. The magnetic moment per atom of the cluster is calculated to be 0.54 mu(B), in good agreement with experimental measurements (0.48 +/- 0.13)mu(B). It confirms our previous assumption that the structural distortion of the Rh-13 cluster from a perfect icosahedron to its ground state geometry decreases its magnetic moment and makes the theoretical calculation close to the experimental measurement.
关键词:
molecules
Journal of Applied Physics
Alloys of PrCo13-xSix (1.5 less than or equal to x less than or equal to 4.0) have been prepared by are melting and subsequent annealing. X-ray powder diffraction proved that the alloys crystallized in the cubic NaZn13-type structure for x=1.5, and in the tetragonal NaZn13-derivative one for x greater than or equal to 2.0. Their Curie temperatures are almost independent of the Si content. Their magnetization curves exhibit a binary-step characteristic. The ac susceptibility curve indicates that there exists a magnetic transition below room temperature. The anomalous binary-step magnetization curves and the ac susceptibility curves versus temperature suggest a metamagnetic transition. (C) 1994 American Institute of Physics.
关键词:
王利刚
,
特古斯
稀土
NaZn13型晶体结构的La(Fe,Si)13化合物由于具有原料价格低廉、磁热效应巨大、环保等优点而备受关注,已经成为国际上公认的最有潜力的室温磁制冷材料之一.本文系统介绍了La(Fe,Si)13化合物的结构和磁热性能,阐述了吸氢、吸氮,稀土元素、Co、B、C、Ca等替代元素对该系列化合物结构和磁热性能的影响,评述了最新的La(Fe,Si)13化合物的制备和加工工艺,最后展望了La(Fe,Si)13化合物作为磁制冷材料的发展趋势.
关键词:
磁制冷
,
磁热效应
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La(Fe,Si)13化合物
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磁熵变
叶四友
,
刘建永
,
杨伟
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2015.08.015
目的：研究获得高质量H13激光涂层的工艺。方法以H13合金粉末为熔覆材料,在H13钢退火基体表面制备H13合金涂层,采用均匀设计试验,利用金相法检测涂层的几何形貌参数,得到涂层宽度回归模型,并验证所建立模型的准确性。利用光学显微镜和扫描电镜分析涂层的显微组织形貌,对涂层成分进行分析,通过显微硬度计测试涂层截面的显微硬度分布。对涂层气孔、裂纹和成分偏析进行分析。结果扫描速度22 mm/s ,激光功率1300 W,送粉速率21 g/min时,H13合金涂层与基体呈良好的冶金结合,涂层内组织均匀致密,无裂纹缺陷,截面显微硬度约600~699HV,是H13基体硬度的2.4~3倍。扫描速度14 mm/s ,激光功率1400 W,送粉速率42 g/min 时,涂层的截面显微硬度约为669~698HV,是基体的2.85~3倍。结论在两种工艺条件下,均能获得质量较优的H13合金涂层。
关键词:
激光熔覆
,
H13合金涂层
,
几何形貌
,
均匀设计
,
回归模型
,
显微硬度
Physica Status Solidi a-Applied Research
The crystal structure and magnetic properties of LaCo13-xAlx compounds have been investigated by X-ray powder diffraction and magnetization measurement. X-ray powder diffraction shows that the compounds crystallize in cubic NaZn13-type structure with lattice parameter a=11.345(2) to 11.473(4) Angstrom in the range of x less than or equal to 2.7, and in the tetragonal Ce2Ni17Si9 structure at x=3. Magnetization measurements reveal that both cubic and tetragonal LaCo13-xAlx are ferromagnetic with Curie temperature higher than 840 K, and the magnetic moment per Co atom in LaCo13-xAlx compounds decreases with Al content.
关键词:
intermetallic compounds;rare-earth;transition
付艳艳
,
周廉
,
于振涛
,
王克光
稀有金属
doi:10.3969/j.issn.0258-7076.2004.01.010
研究了Ti-13Nb-13Zr合金在β相区和(α+β)两相区固溶和时效处理后其合金力学性能及组织变化规律. 分析发现在β相区固溶的合金, 水冷时生成针状马氏体α′, 空冷时生成亚稳定β相和少量αp, 在(α+β)两相区固溶生成β转和αP. 在β相区和(α+β)两相区固溶试样经时效后, 晶粒内部主要析出点状和棒状αS. 在750 ℃/1 h固溶(WQ)和低温510 ℃/6 h时效的合金抗拉强度高、塑性较高、弹性模量低, 可以满足人体植入要求.
关键词:
Ti-13Nb-13Zr
,
力学性能
,
显微组织
田伟红
,
郭杨阳
,
李轩鹏
,
郭亚鑫
,
范爱兰
,
刘小萍
,
唐宾
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2015.05.011
目的：提高医用钛合金的耐磨损性能。方法应用等离子渗氮技术在Ti13 Nb13 Zr基材上制备改性层,并对改性层组织、成分及硬度进行测试。利用往复磨损试验机研究改性层在干摩擦条件下的摩擦磨损性能,并与未处理的基材进行对比。结果 Ti13 Nb13 Zr合金表面经渗氮后形成致密均匀的改性层,硬度高达1110 HV0.025,改性层的磨损体积约为基材的1/23。结论等离子渗氮技术有效地改善了Ti13 Nb13 Zr合金的摩擦磨损性能。
关键词:
Ti13 Nb13 Zr
,
等离子渗氮
,
硬度
,
摩擦性能
张成路
,
申洪江
,
邹立伟
,
许永廷
,
广东
,
李元东
,
王杨
,
王利东
应用化学
doi:10.3969/j.issn.1000-0518.2009.10.011
以3,5-二甲氧基苯甲酸(1)为起始原料, 经过甲醇酯化、氢化铝锂还原、四溴化碳溴代和Wittig-Horner反应,高产率的合成了Wittig-Horner试剂(5). 化合物5与对羟基苯甲醛(6)的羟基保护产物(7)偶联得到化合物(8),后者经去甲氧基亚甲基保护和仿生氧化偶联反应成功地全合成了(E)-脱氢二聚白藜芦醇-11,11′,13,13′-四甲醚(10). 通过~1H NMR、~(13)C NMR、IR、HRMS等测试技术确定化合物10为二聚芪类化合物(E)-脱氢二聚白藜芦醇-11,11′,13,13′-四甲醚,总收率48.93%.
关键词:
白藜芦醇
,
氧化偶联
,
二聚芪类化合物
,
(E)-脱氢二聚白藜芦醇四甲醚
