吴玉锋
,
杜文博
,
聂祚仁
,
苏学宽
,
左铁镛
金属学报
doi:10.3321/j.issn:0412-1961.2006.05.008
以Al-M(M=Sr,Nd)二元相图、Miedema生成热模型和Toop模型为基础,建立了Mg-Al-M三元合金熔体中Al-M金属间化合物析出行为的热力学计算模型,并采用该模型对Mg-8Al-3.5Sr熔体中Al-Sr金属间化合物的析出温度进行了计算,结果与文献基本吻合.利用该模型对一定温度下Mg-9/6Al-M(M=Sr,Nd)熔体中优先析出Al-M金属间化合物所需M的最低含量进行了计算.根据计算结果,对Al-M金属间化合物在Mg-9/6Al-M合金熔体中的析出行为以及对合金力学性能可能的影响进行了分析和比较,提出了采用稀土Nd和碱土Sr复合添加来制备耐热镁合金的思路.
关键词:
Mg-Al基合金
,
Miedema生成热模型
,
Toop模型
,
Al11Nd3
,
Al2Sr
刘勤
,
夏锄
,
刘晓东
金属学报
在170,190,210,230,250℃的温度下,采用3.7×10~2,7.4×10~2和1.1×10~(-1)min(-1)的应变速率(平均)对Zn-5%Al共晶合金的m-C-δ(或m-k-δ)关系曲线(简称m-δ关系曲线)进行了测定.所有的曲线均随应变的δ增加而快速上升.俟达到某一定的应变量(极限应变量δ1)后。开始缓慢下降并保持平稳直至断裂.Zn-5%A1共晶合金的m-δ关系曲线不存在k_(?)=k_I(k_(I 1),k_(I 2),k_(I 3),……)=k_F(或C_0=C_I(C_(I 1),C_(I 2),C_(I 3),……)=C_F=1)的简单情况.可应用m-δ方程式[4,5]对曲线上各点C值(包括所有的C_I和C_F值)进行计算.C值随δ值的增加成近似的直线上升.直线的斜率在极限应变(δ1)处突然减小.
关键词:
Journal of Alloys and Compounds
The crystal structure, activation performance. hydrogen storage properties. thermodynamics, pulverization resistance and absorption/desorption kinetics of LaNi(13.8)Al(10)M(0.2) (M = Ni, Cu, Fe, Al, Cr, Mn) hydrogen storage alloys were investigated systemically The absorption/desorption pressure-composition (PC) isotherms and kinetics were measured at a temperature range of 413-493 K by the volumetric method It was found that all the investigated alloys showed CaCu(5) type of hexagonal structures and the partial substitution of M for Ni resulted in the increase of the unitcell volumes in an orderof Ni < Cu < Fe < Al < Cr < Mn The activation became easier with Cr substitution for partial Ni but a little harder for the Cu, Fe, Mn, Al contained alloys M elements decreased the absorption/desorption plateau pressure in an order of LaNi(4)Al > LaNi(3.8)Al(10)Cu(0.2) > LaNi(3.8)Al(10)Fe(0.2) > LaNi(3.8)Al(10)CrO(2) > LaNi(3.8)Al(10)Mn(0.2) > . There were linear relationships between plateau pressure and cell volume of tile investigated alloys The absolute values of the enthalpy for all the alloys were increased with M substituteJ for partial Ni. Al and Cu improved the pulverization resistance. The absorption kinetics was very fast while the necessary times taken by LaNi(3.8)Al(1.0)M(0.2) alloys to desorb 90% of their maximum hydrogen capacity were increased in an order of Ni < Cu < Fe < Al < Cr < Mn. (C) 2009 Elsevier B V All rights reserved
关键词:
Metal hydride;Hydrogen absorbing materials;Gas-solid reactions;Thermodynamic properties;electrochemical properties;thermodynamic properties;structural-properties;hydrides;lani5;absorption;intermetallics;electrodes;stability;system
汪洁
,
包小倩
,
高学绪
,
张茂才
,
朱洁
,
张从阳
金属功能材料
采用真空快淬设备以辊速5 m/s、10 m/s、15 m/s、20 m/s、30 m/s制备了Nd60Fe30M10(M=Al,Si,Ga)系的.非晶带",研究了制备速度对"非晶带"永磁性能和结构的影响.实验结果表明:Nd60Fe30Si10和Nd60Fe30Ga10同经典合金Nd60Fe30Al10一样,也显示出非晶永磁性能,并且比相同条件下制备的Nd60Fe30Al10"非晶带"的永磁性能更好;三种"非晶带"的矫顽力随辊速的降低而提高.对Nd60Fe30Al10"非晶带"的TEM分析表明,以30 m/s辊速制备的"非晶带",有2～5 nm的析出物弥散分布在非晶基体上;而以5 m/s辊速制备的"非晶带",有10 nm左右和150～200 nm的析出物分布在非晶基体上.析出物的生成,促进了矫顽力的提高.
关键词:
Nd60Fe30M10合金
,
非晶带
,
永磁性能
,
组织结构
Materials Transactions
ln-situ SEM observations of fracture processes in two 6061 Al alloy composites reinforced with coarse and line SiC particles, respectively. were carried out to clarify their fracture mechanisms. It was found that in the coarse particle reinforced composite, void were formed in the matrix around SiC particles ahead of the main crack tip. then coalesced with each other, and finally connected with the main crack tip. Causing propagation of the main crack. However. in the fine particle reinforced composite, multiple in micro-cracks were formed at the boundaries between SiC particle clusters and surrounding matrix or within the clusters. then connected with each other, and finally joined with the main crack tip. leading to crack branching and growth of the main crack, Crack branching, multiple cracking and crack deflection were proposed to contribute to the enhanced fracture toughness in the fine particle reinforced composite compared with the coarse particle reinforced composite.
关键词:
fracture processes;fracture toughness;metal matrix composites;crack;growth driving force;aluminum alloy;reinforced aluminum-alloy;metal-matrix composite;toughness;crack;simulation;behavior
Journal of the Less-Common Metals
High-field magnetization measurements were performed on magnetically aligned samples of quasi-ternary compounds of the Pr2(Fe,M)14B series with M = Al, Ga and Si at 4.2 K in magnetic fields up to 35 T. The saturation magnetization and anisotropy constants were derived as functions of composition. The results suggest that the transition in the magnetization curves of these series is probably not a first-order magnetization process (FOMP).
关键词:
crystal;anisotropy;pr2fe14b
徐益军
,
唐有根
,
曹泽华
,
杨幼平
,
卢凌彬
金属功能材料
doi:10.3969/j.issn.1005-8192.2003.02.003
采用固态烧结法制备了Mg1.7M0.3(M＝Mg、Ti、Al)Ni贮氢合金,X射线衍射分析结果表明,适当提高烧结温度有利于Mg2Ni相的形成;Ti对Mg的取代未引起合金相结构的明显变化,而Al取代Mg除有Mg2Ni相外,还有一呈立方晶体结构的新相生成.Ti、Al对Mg的取代,不仅提高了Mg2Ni合金的放电容量,同时也提高了合金的循环寿命.
关键词:
固态烧结
,
镁基合金
,
镍氢电池
Journal of Magnetism and Magnetic Materials
The structural and magnetic properties of the Er2Fe15M2 compounds with M = Mn, Fe, Ni, Al, Ga and Si have been studied. X-ray diffraction and thermomagnetic curve measurements show that all compounds crystallize in the Th2Ni17-type of structure. The X-ray diffraction patterns of the aligned samples indicate that at room temperature all compounds have planar anisotropy. The effects of the substitution for Fe of various elements on the magnetic properties such as Curie temperature and spontaneous magnetization are discussed. Substitution of Ni for Fe leads to the strongest increase of T-c and the smallest decrease of M-T The magnetocrystalline anisotropy of these compounds has been investigated. (C) 1998 Elsevier Science B.V. All rights reserved.
关键词:
anisotropy - magnetocrystalline;rotation magnetic alignment;solid-solutions;mossbauer;substitution;alloys;fe-57
