Yuanyuan Song Xiuyan Liy Lijian Rong Yiyi Li
材料科学技术（英）
The thermal stability of the reversed austenite in a low carbon Fe-13%Cr-4%Ni-Mo (in wt pct) martensitic stainless steel was investigated by X-ray diffraction (XRD) and superconducting quantum interference device (SQUID) magnetometer. Different amount of the reversed austenite was obtained by controlling tempered temperature. It was found that the amount of the reversed austenite increased after keeping the specimens at liquid nitrogen temperature for 72 h. The mechanism of the anomalous phase transformation from martensite to austenite was discussed.
关键词:
Low temperature
,
Martensite
,
Austenite
,
Phase transformation
,
Magnetization vs. temperature
Yuanyuan Song Xiuyan Liy Lijian Rong Yiyi Li
材料科学技术（英）
The thermal stability of the reversed austenite in a low carbon Fe-13%Cr-4%Ni-Mo (in wt pct) martensitic stainless steel was investigated by X-ray diffraction (XRD) and superconducting quantum interference device (SQUID) magnetometer. Different amount of the reversed austenite was obtained by controlling tempered temperature. It was found that the amount of the reversed austenite increased after keeping the specimens at liquid nitrogen temperature for 72 h. The mechanism of the anomalous phase transformation from martensite to austenite was discussed.
关键词:
Low temperature
,
Martensite
,
Austenite
,
Phase transformation
,
Magnetization vs. temperature
路艳罗
,
卫敏
,
杨文胜
,
D.G.Evans
,
段雪
应用化学
doi:10.3969/j.issn.1000-0518.2002.11.005
由高温焙烧法制备层状前驱体Nax[Li1/6Mn5/6]O2,再经离子交换反应得到O2结构层状产物Liy[Li1/6Mn5/6]O2. 采用离子交换和元素分析推测前驱体中Li+位于层板上. XRD测试结果表明,Liy[Li1/6Mn5/6]O2属六方晶系,P3ml空间群;激光粒度分析仪测定Na0.06Li0.65[Li0.10Mn0.88]O2的最可几粒径为2.88 μm;BET法测定其比表面积为4.68 m2/g;TEM显示其形貌为存在缺陷的层状六方结构. XRD和元素分析结果表明,反应物n(Na)/n(Mn)比直接影响着前驱体及最终产物的晶体结构和化学组成.
关键词:
Liy[Li1/6Mn5/6]O2
,
层状材料
,
晶体结构
,
化学组成
粟智
,
刘丛
,
徐茂文
应用化学
doi:10.3724/SP.J.1095.2010.90106
以Na_2CO_3、(CH_3CO_2)2Mn·4H_2O、Y_2O_3和CH_3COOLi·2H_2O为原料,采用高温固相法经过2次灼烧和水热离子交换法得到一系列钇掺杂的LiMn_(1-x)Y_xO_2(x:0.01,0.02,0.03,0.05)化合物.通过XRD、XPS、循环伏安及恒电流充放电测试技术,研究了钇掺杂离子对合成正极材料结构及电化学性能的影响.结果表明,所得产物均具有单斜层状结构.合适的钇掺杂可以起到扩展锂离子脱嵌通道和稳定骨架结构的作用,钇离子的引入部分取代原有的三价锰离子,由于钇离子的离子半径较三价锰离子大,因此稀土掺杂锰酸锂材料的晶胞参数比未掺杂材料大,在一定程度上扩充了锂离子迁移的三维通道,更有利于锂离子的嵌入与脱嵌,提高单斜层状LiMnO_2材料的电化学循环可逆性及循环稳定性.通过对所得化合物进行了钇掺杂量及电化学性能的研究,得到性能比较优良的LiY_(0.021)Mn_(0.979)O_2化合物,其首次放电比容量为125.7 mA·h/g,100次循环以后,放电比容量达212.1 mA·h/g,远高于未掺杂材料的放电容量138 mA·h/g.交流阻抗测试结果表明,Y~(3+)的掺入能降低材料的电化学反应阻抗和提高材料中Li~+的扩散能力.
关键词:
单斜LiMnO_2
,
锂离子电池
,
正极材料
,
钇掺杂
,
电化学性能
李志宏
,
柳卫平
,
白希祥
,
郭冰
,
连钢
,
颜胜权
,
王宝祥
,
陆昀
,
曾晟
,
苏俊
原子核物理评论
doi:10.3969/j.issn.1007-4627.2005.01.006
利用8Li次级束测量了质心系能量7.8 MeV 2H(8Li, 9Li)1H反应的角分布, 导出了8Li(d, p)9Li反应的天体物理S因子及9Li→8Li+n虚衰变的渐近归一化系数.
关键词:
8Li(d,p)9Li反应
,
角分布
,
天体物理S因子
,
渐近归一化系数
HUANG Jianshun CHEN Junming Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
China Research Associate
,
Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai 200050
,
China
金属学报(英文版)
Crystal structure of γ-Li_xFe_2O_3,inserted Li electrochemically,was studied by Moss- bauer spectroscopy together with X-ray diffraction,XPS and electrochemical method,On the insertion of Li at low current density,the crystal structure is keeping original spinel; while at higher current density or by thermal activation,owing to violent movement of Li~+ ions,part of crystal structure transforms into rock type similar to face-centered cubic structure of ferrous oxide.The transition channels during insertion of Li~+ ions and limitation of Li~+ ions inserted were discussed.
关键词:
null
,
null
,
null
Journal of Materials Research
The effect of Li(3)N additive on the Li-Mg-N-H system was examined with respect to the reversible dehydrogenation performance. Screening Study with varying Li(3)N additions (5, 10, 20, and 30 mol%) demonstrates that all are effective for improving the hydrogen desorption capacity. Optimally, incorporation of 10 mol% Li(3)N improves the practical capacity from 3.9 wt% to approximately 4.7 wt% hydrogen at 200 degrees C, which drives the dehydrogenation reaction toward completion. Moreover, the capacity enhancement persists well over 10 de-/rehydrogenation cycles. Systematic x-ray diffraction examinations indicate that Li(3)N additive transforms into LiNH(2) and LiH phases and remains during hydrogen cycling. Combined structure/property investigations suggest that the LiNH(2) "seeding" should be responsible for the capacity enhancement, which reduces the kinetic barrier associated with the nucleation of intermediate LiNH(2). In addition, the concurrent incorporation of LiH is effective for mitigating the ammonia release.
关键词:
complex hydrides;improvement;mixtures;imides;amide;h-2
MANG Weishi WANG Guozhi ZHANG Yongchang HU Zhuangqi SHI Changxu Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China Yongchang Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
A rapidly solidified microcrystalline Al-Li-Cu-Mg-Zr alloy and its superplasicity have been investigated.An optimum tensile elongation of 585% was obtained at 540℃ and strain rate 1.67×10~(-2)s~(-1).The superplastic Al-Li alloy is manufaetured using thermomechanical pro- cessing:solution,overaging,warm rolling and recrystallization.Microstructural changes in thermomechanical processing and cavitation occurred during superplastic deformation have been observed.The superplastic failure of alloy may be caused mainly by nucleation and growth of cavities as well as the linkage around grains.
关键词:
superplasticity
,
null
,
null
,
null
