X.G
,
Yang
,
Q.A. Zhang
,
K. Y Shu
,
YL. Du
,
YQ. Lei and Q.D. Wang (Department of Materials Science and Engineering
,
Zhejiang University
,
Hangzhou 310027
,
China )W.K. Zhang(Department of Applied Chemistry
,
Zhejiang University of Technology
,
Hangzhou 3100l4
,
China )G.L. Lu(Central Lab
,
Zhejiang University
,
Hangzhou 310028
,
China)
金属学报(英文版)
The annealing treatment was found to improve the cyclic stability but to degmde discharpe capacity, activation and high-rate discharpeability for the Ti-substituted AB2type alloy electrode. A larper polarization was found in the annealed alloy because of its poor discharpe kinetics resulted hem the structural homogeneity. At larae discharpe cumnts, the hydmpen dchsion in the bulk of the alloy was mpaofed as the mte-determining step. Based on the P ressure-composition isotherm measurement, we concluded that the decrease in discharpeability of the annealed alloy is owing to the low and flat pressure plateau, as well as the large hysteresis, but the hydrgen stomge density almost remains unchangeable after annealing.
关键词:
AB_2
,
null
,
null
,
null
,
null
,
null
严东旭
,
刘天伟
,
龙重
,
白彬
,
张鹏程
,
黄河
,
郎定木
,
王晓红
,
朱建国
材料保护
采用单一的表面改性技术难以提高贫铀钛合金(Du-Ti)的耐蚀性能.采用等离子体浸没离子注入技术依次在Du-Ti合金表面注入N和Ti,再利用非平衡脉冲磁控溅射技术制备多层Ti/,TiN,研究了膜层的形貌、结构及耐蚀性能.结果表明:膜层厚约3μm,呈柱状结构,致密,但存在一些微缺陷,膜基结合紧密;膜层出现面心立方结构的TiN和密排六方的Ti,在DU-Ti合金界面形成了少量的UO2,没有铀的氮化物;膜层耐蚀性能较基体得到较大提高;微观缺陷是TiN层局部片状脱落的主要原因,外层TiN出现片状脱落后.注入层和内层Ti/TiN多层膜仍能有效保护基体.
关键词:
等离子体浸没离子注入
,
非平衡磁控溅射
,
复合膜
,
DU-Ti合金
,
电化学腐蚀
,
耐蚀性
郭洪民
,
杨湘杰
中国有色金属学报
采用具有自主知识产权的流变铸造工艺,研究了流变压铸YL112合金铸件中的气孔、流变压铸件的热处理和力学性能.结果表明:采用低固相率半固态浆料的直接压铸工艺可提高压铸件的致密性和力学性能,尤其伸长率提高更为显著,可采用热处理可进一步提高YL112合金的力学性能.在500 ℃固溶处理3 min后,YL112合金的共晶Si已经破碎并球化,固熔处理30 min 的T6热处理工艺可使YL112合金的强度和塑性达到比较好的匹配.
关键词:
流变成形
,
压铸
,
微观组织
,
力学性能
,
热处理
郭洪民
,
杨湘杰
中国有色金属学报
将剪切低温浇注半固态(LSPSF)浆料制备工艺与传统高压铸造工艺衔接,研究出一种半固态浆料直接成形工艺--流变压铸技术.结果表明:LSPSF工艺可在15~20 s制备出初生α(Al)形状因子为0.93,晶粒尺寸为70 μm且分布均匀,初生α(Al)内部没有夹裹液相的YL112铝合金半固态浆料;与传统压铸相比,流变压铸可改善YL112合金铸件的微观组织,半固态浆料在二次凝固中发生体积凝固,铸件微观组织细小且分布均匀.该LSPSF流变铸造工艺与传统压铸工艺衔接简便,半固态浆料输送平稳,具有较强的可操作性.
关键词:
流变成形
,
半固态
,
微观组织
,
压铸
,
YL112铝合金
颜莹
,
张彩碚
,
刘羽寅
,
雷家峰
金属学报
doi:10.3321/j.issn:0412-1961.2002.z1.048
本文研究了在氢压为0.05 MPa、保温100 min时的T52YL钛合金吸氢行为和组织结构变化及氢环境对其机械性能的影响.结果表明:吸氢温度在374-715℃范围内,盘材和棒材的变化规律相似,先随温度的提高吸氢量逐渐增加,并且在500℃左右有一个吸氢峰,含氢量约为2.0%(质量分数),然后随温度继续提高吸氢量变化不大,基本维持在(1-1.5)%;微量氢已使α相中析出γ氢化物,随氢含量的增加氢化物不断增多、增大;在氢环境中氢脆敏感性很弱.
关键词:
钛合金T52YL
,
吸氢
,
组织结构
王文昌
,
张垒
,
孔德军
,
付贵忠
,
叶存冬
材料热处理学报
利用阳极氧化法在YL113铝合金表面制备了一层氧化膜,通过SEM、XRD、EDS、XPS等手段对其表面-界面形貌、物相、化学元素组成和原子结合能谱进行了分析,对其表面和结合界面化学元素进行了面扫描和线扫描分析,并对氧化膜界面结合形式进行了表征.结果表明,阳极氧化后Al原子和O原子在氧化膜表面产生分层富集现象,其原子分数之比接近2:3,所生成的氧化膜组成物为α-Al2O3+γ-Al2O3;Al2p峰结合能为74.37 eV,以Al3+形态存在,O1s峰结合能为531.82 eV,以O2-形态存在,氧化膜是以Al2O3形式存在;Al和O原子在氧化膜结合界面形成富集层,氧化膜与基体形成化合物型界面+扩散型界面组合形式;在结合界面处出现大量的小岛及锚点,氧化膜表现为较强的界面结合力.
关键词:
阳极氧化膜
,
XPS分析
,
表面与界面
,
面扫描
,
线扫描
Applied Physics a-Materials Science & Processing
We have studied the influence of C and Si ion implantation with different implantation doses on yellow luminescence (YL) from GaN. Three kinds of GaN samples were used. In their as-grown states, #1 samples had strong YL, #2 samples had no YL, while #3 samples had weak YL. Our experimental results show that: (i) after annealing at 950 degreesC, the YL intensity for Si ion implanted #1 sample decreased with increasing implantation dose, while that for C ion implanted #1 sample exhibited a reverse rule; (ii) for #2 samples, C ion implantation produced much stronger YL than Si ion implantation did after annealing at 950 degreesC; (iii) the YL intensity sequence for Si ion implanted and 950 degreesC annealed #1, #2, and #3 samples was consistent with that for the unimplanted #1, #2, and #3 samples. However, the YL intensity sequence for the C ion implanted and 950 degreesC annealed #1, #2, and #3 samples reversed with that for the unimplanted ones. In order to explain all these phenomena, we suggested a physical model which claims that the deep C center is another important origin of YL in GaN, and during C ion implantation, the C ion prefers to combine with a V-Ga to form a C-Ga.
关键词:
detected magnetic-resonance;vapor-phase epitaxy;undoped gan;photoluminescence;vacancies;nitrides
Physica B-Condensed Matter
We have studied the effects of Si ion implantation and post-annealing on yellow luminescence (YL) from GaN. Two types of GaN samples grown by the metal-organic chemical vapor deposition method and labeled as GaN1 and GaN2 were studied. The PL spectrum of the as-grown GaN1 sample was dominated by a strong YL and that of the as-grown GaN2 sample was almost free from YL. After Si ion implantation with doses of both 1.3 x 10(13) and 1.0 x 10(16)cm(-2), the intensity ratios of YL to near band edge (NBE) emission (I-Y/I-NBE) for the GaN1 samples decreased markedly compared with those of the corresponding unimplanted ones both before and after post-annealing at temperatures up to 950degreesC. However, for the Si-ion-implanted GaN2 sample with a dose of 1.3 x 10(13)cm(-2), I-Y/I-NBE increased compared with that of the as-grown one both before and after post-annealing. Besides, the I-Y/I-NBE for Si-ion-implanted GaN1 with a dose of 1.3 x 10(13) cm(-2) increased monotonically with annealing temperature. Our results show that only the Si ion implantation being accompanied with high-temperature post-annealing could produce YL. The possible reasons for the marked reduction in I-Y/I-NBE for the GaN1 sample after Si-ion-implantation have been discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
关键词:
photoluminescence;yellow luminescence;ion implantation;GaN;detected magnetic-resonance;vapor-phase epitaxy;laser-diodes;undoped;gan;photoluminescence;vacancies;layers;origin
