X Y He
,
H Y Deng
,
R Li
金属学报(英文版)
Corrosion monitoring techniques were performed on X70 steel in saline solution saturated with CO2 with and without thiourea additives within the concentration range 5mg/L-25mg/L.It was found that when the concentration of the inhibitors were increased the inhibitor efficiencies ,IE.and IE of thiourea varied with solution temperature ,immersion time. The results indicated that thiourea had the highest inhibiton efficiency.The potentiondynamic polarization studies revealed that thiourea are mixed tye inhibitor that mainly restrain the anodic process.
关键词:
corrosion
,
null
,
null
,
null
Applied Physics Letters
The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]
关键词:
ferroelectricity;polarization
李悦
,
邓爱红
,
刘莉
,
王康
,
谢莎
材料研究学报
利用x射线衍射(xRD)和慢正电子束分析(SPBA)技术研究高温退火后含He钛膜的微观结构和钛膜内He相关缺陷的演化.XRD分析表明,高温退火后Ti和Si在高温下发生反应形成稳定的多晶TiSi2化合物,He原子的掺入会影响TiSi2晶体的择优取向,而对TiSi2晶粒尺寸的影响较小.SPBA结果表明,室温下,钛膜内的缺陷浓度或尺寸会随着掺He浓度的增加而增大;高温退火后,当He浓度小于5％(原子分数,下同)时(除2％外),钛膜内的He相关缺陷浓度随着He浓度增加相应地增加.当He浓度增加到14％时,高温会使较高浓度的He原子、He-空位复合体以及小He泡迁移聚集形成一些尺寸较大He泡,而较大He泡周围与He相关的小尺寸缺陷的浓度则会发生相应地减少.
关键词:
金属材料
,
含He钛膜
,
直流磁控溅射
,
He相关缺陷
,
XRD
,
SPBA
施立群
,
金钦华
,
刘超卓
,
徐世林
,
周筑颖
原子核物理评论
doi:10.3969/j.issn.1007-4627.2005.01.045
研究了用He/Ar混合溅射气体的直流磁控溅射制备钛膜中He的掺入现象.分析结果表明,大量的He原子(He/Ti原子比高达56%) 被均匀地引入到Ti膜中,He含量可由混合溅射气体的He分量精确控制.通过调节溅射参数,可实现样品中He的低损伤引入.研究还发现,溅射沉积的含氦Ti膜具有较高的He成泡剂量和高的固He能力,这可能是溅射沉积形成了纳米晶Ti膜所致.纳米晶Ti膜较粗晶材料具有很高浓度的He捕陷中心,使He泡密度增大而泡尺寸减小.随He引入量的增加,Ti膜的晶粒尺寸减小,He引起的晶体点阵参数和X射线衍射峰宽度增大,晶体的无序程度增加.
关键词:
氦
,
损伤
,
泡
,
钛膜
,
溅射沉积
材料科学技术（英文）
The glass-forming ability (GFA) of Nd(70-x)Fe(20)Al(10)Y(x) and Nd(60-x)Fe30Al(10)Y(x) (0 less than or equal to x less than or equal to15) alloys produced by Cu mold casting was investigated. Except Y = 5 at. pct, bulk amorphous Nd(70-x)Fe(20)Al(10)Y(x) alloys up to 2 mm in diameter were obtained. The GFA for Nd(60-x)Fe(30)Al(10)Y(x) alloys, however, was found to decrease with increase of Y due to the increasing compositional deviation from the original eutectic point of Nd(60)Fe(30)Al(10) alloy. The Nd(60)Fe(20)Al(10)Y(10) and Nd(60)Fe(30)Al(10) alloy exhibit the largest GFA and can be cast into bulk amorphous cylindrical specimens of 3 mm in diameter. The melting temperature or/and the reduced crystallization temperature is closely related to the GFA of Y-containing alloys. The bulk amorphous cylinder for the Nd(55)Fe(20)Al(10)Y(15) alloy shows a distinct glass transition temperature and a wide supercooled liquid region before crystallization. The crystallization temperature, T(g), and the supercooled liquid region, DeltaT(x), are 776 K and 58 K, respectively, The GFA and thermal stability of the Nd-Fe-Al-Y alloys were discussed.
关键词:
Nd-based alloys;glass forming ability;liquidus temperature;thermal;stability;supercooled liquid region;bulk amorphous-alloys;metallic glasses;transition temperature;thermal-stability;atomic size;ni alloys;cu;alloys;diameter;tm
ZHANG Lei WANG Peixuan TAO Rong MA Ruzhang ZHANG Guoguang University of Science and Technology Beijing
,
Beijing
,
China professor
,
Department of Materials Physics.University of Science and Technology Beijing.Beijing 100083
,
China
金属学报(英文版)
Nucleation and growth of He bubbles at different annealing temperatures T≤1023 K in stain- less steels HR-2 and SS321,implanted with He~+(40-70 keV.1×10~(16)-6× 10~(17) He~+/cm~2),were ohserved under TEM.T=0.45T_m seems to be a transition temperature.The He bubbles continue mainly their nucleation at 0.3T_m< T<0.45T_m,and grow predominantly at T≥0.45T_m,due probably to migration and coalescence by surface diffusion of metal atoms around the bubbles.The apparent activation energies for the growth are found to he 0.41 and 0.31 eV for HR-2 and SS321 respectively.The bubble density in HR-2 is greater than that in SS321 within whole measuring temperature range,and the onset temperature of rapid swelling is also higher.It is believed that the resistance of HR-2 to He is superior to that fo SS321.
关键词:
stainless steel
,
null
,
null
,
null
,
null
Journal of Nuclear Materials
Due to its inert reactivity with almost elements, He-3 produced from tritium decay has extremely detrimental effects on the tritide. To refrain from this He-3-induced damage, an efficient way is to increase the stability of He-3 in metal tritide by alloying. Using a first-principles discrete variational method in two cluster models, one for a low He-3 concentration and the other for a high He-3 concentration, the authors study the alloying effect of 3d and 4d transition metals on the stability of He-3 in TiT2 system. It is found that the preferring and metastable sites of He-3 are affected by He-3 concentration : He-3 prefers to stay at original tetrahedral interstitial site when He-3 concentration is low but moves to octahedral site when He-3 concentration is high enough. A criterion of alloying effect is proposed, according to which Nb, Y, Zr, Pd, Ru, Tc, Rh, Cr, Mo and Ag are suggested to be the beneficial alloying elements for increasing the stability of He-3 in the alloyed TiT2 with a low He-3 concentration and Y, Nb, Mo, Zr, Cr, Tc, Ru, Rh and Cu for that with a high He-3 concentration. Our results of alloying effect are supported by the positron annihilation spectroscopy (PAS) measurements for He-implanted Ti, TiMoYAl and TiZrYAl films. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
electronic population analysis;molecular wave functions;hydrogen;storage alloys;intermetallic hydride;bubble formation;iron clusters;helium;tritides;lcao;overlap
Physica B-Condensed Matter
The magnetic properties and magnetocaloric effect of Tb(1-x)Y(x)CoC(2) (x = 0, 0.1, 0.2, 0.3, 0.4) compounds have been investigated systematically. All the compounds undergo second-order transitions from paramagnetic to ferromagnetic states without thermal and magnetic hysteresis. With increasing Y content from 0 to 0.4, the Curie temperatures decrease nearly linearly from 28 to 18 K. The nature of the second-order phase transitions can be confirmed by Arrott plots. For Tb(0.6)Y(0.4)CoC(2) compound, the maximum value of the magnetic entropy change -Delta S(M) at 20 K is 9.35 J kg(-1) K(-1) for an external field change of 5T (5.14 J kg(-1) K(-1) for 2T). The large reversible magnetic entropy change makes Tb(0.6)Y(04)CoC(2) compound an attractive candidate for the application at hydrogen liquefaction temperature. (C) 2010 Elsevier B.V. All rights reserved.
关键词:
Curie temperature;Magnetocaloric effect;Magnetic properties;ac susceptibility
