掺微量Zr的Al-Mg合金的原子成键与力学性能

运用固体经验电子理论(EET),对掺微量Zr的Al-Mg合金的价电子结构进行计算。从价电子结构层次阐明加入微量Zr对Al-Mg合金原子成键产生的强烈作用,是合金硬度、强度和晶粒热稳定性提高的内在原因。结果表明,Zr与Al原子存在强的结合倾向,易在合金熔体中生成粗大的初生Al3Zr颗粒,起非匀质形核细化晶粒作用。在合金凝固过程中,易形成Al-Zr晶胞原子偏聚区,在基体析出细小弥散的次生Al3Zr颗粒,起到增强合金基体的共价键络的作用。     

Al-Zn合金GP区的价电子结构及界面能

运用固体经验电子理论计算Al-Zn合金GP区的价电子结构,并运用其价电子结构的信息计算其与母相的界面能。结果表明,由于GP区晶胞最强键上的共价电子数远比纯Al晶胞最强键共价电子数多,Al原子极易与Zn原子形成共价键,所以在Al-Zn合金中即使以最快速度淬火,也能在淬火过程中形成GP区,且合金硬度在GP区开始形成时就稳步上升,而于中间相形成前达到最大值。运用EET理论计算界面能是简便且行之有效的方法。     

Al-Mg-Si合金GP区的原子键络与强化作用

运用固体经验电子理论，对Al—Mg—Si合金GP区（L10型）价电子结构进行了计算，结果表明：L10型GP区的最强键与次强键比基体最强键强很多，其主键络骨架对合金键络起到增强作用；而其相邻的（111）晶面上的共价键络较强，使得该面滑移时较基体更困难，从而起到提高合金硬度的作用。     

用价电子理论分析Y对Mg—Al合金力学性能的影响

基于EET理论,计算Y元素加入Mg-Al合金后形成的Mg-Al-Y固溶体、第二相Al2Y的价电子结构,研究价电子结构与合金固溶强化、第二相强化、高温稳定性的关系.Mg-Al-Y最强键共价电子对数nA值和共价电子密度pvc值均大于a-Mg的nA值和pvc值,表明Y元素的固溶有利于基体强度的提高.第二相Al2Y的最强键(nA=0.39704)的键合强度远大于基体a-Mg(nA=0.11199)的键合强度.因此,Al2Y极大的阻碍了位错的运动.提高了合金的强度.Al2Y的单位体积成键能力FvAl2Y值为103.81,与y-Mg17Alt2(Fvy-Mg17A112=44.22)相比较,Al2Y的高温稳定性更好.其存在有利于改善Mg-Al合金的高温性能.     

Al-Cu合金析出相的原子键强与性能

应用固体经验电子理论(EET),对Al-Cu合金时效过程中θ″、θ′和θ相的键络进行计算.结果表明,时效初期形成的θ″相中,最强共价键为Al-Cu键.合金中θ″相溶解并析出相时,Cu原子状态发生明显变化,使得Cu原子的共价电子数有较大幅度的提高,此时形成的亚稳相的最强共价键仍为Al-Cu键,较θ″相的最强Al-Cu键提高一倍.时效后期,合金析出稳态θ相,最强键由θ′相的Al-Cu键转为Cu-Cu键,而Al-Cu键成为次强键.依靠Cu原子提供较多的共价d电子,使θ相的共价键络较θ′亚稳相的共价键络强度进一步提高.     

间隙杂质对Ti—Al合金价电子结构及相变温度的影响

Ｔｉ－Ａｌ合金相图因其金属间化合物优异的高温性能目前受到广泛研究，本文根据余氏理论的平均晶胞模型及键能公式，分析了间隙元素对Ｔｉ－Ａｌ系α，β，γ（ＴｉＡｌ）相价电子结构的影响，计算了间隙元素对这些相变点温度的影响。结果表明，间隙元素使Ｔｉ－Ａｌ合金某些相变点降低很大，从而解释了一些有争议的实验结果。     

Al3Fe价电子结构及其对Al-Fe合金性能的影响

基于EET理论计算并分析Al3Fe的价电子结构与合金第二相强化、高温稳定性、范性的关系.结果表明,Al3Fe最强共价键(n1(Al3Fe)=1.0834)键合强度远大于γ(-Mg(17)Al(12))(n1(γ(-Mg(17)Al(12))=0.3455)和Mg2Si(n1(Mg2Si)=0.3241)的键合强度,有利于合金强度的提高.Al3Fe的成键能力F(ν)(Al3Fe)(729.87)远大于γ(-Mg(17)Al(12))(F(ν)(γ(-Mg(17)Al(12)))=44.22)和Mg2Si(F(ν)(Mg2Si)=42.76)的成键能力,有利于合金稳定性的增强.Al3Fe的晶格电子密度ρ1(Al3Fe)(8.6357%)小于α-Al(ρ1(α-Al)=15.6808)与Mg2Si(ρ1(Mg2Si)=21.6478)的晶格电子密度,Al3Fe晶胞中强、弱键分布n(α)不均,不利于合金的范性.     

Al-Cu-Mg合金析出相的原子成键与性能

根据固体与分子经验电子理论（EET），计算Al-Cu-Mg合金时效初期形成的GPB区和S″相的价电子结构。结果表明，GPB区具有较强的共价键络，而S″具有较强的总共价成键能，这两种析出相的主体共价键络都对合金基体具有增强作用。同时从价电子结构层次和析出相中Al原子的总成键能力合理解释了GPB区演化为S和S相的相变机理，并说明了相变对合金的强化作用。     

金属间化合物Ni3Al中B在晶界的偏聚研究

对比了Ｎｉ３Ａｌ－Ｂ合金的均匀化态和８００℃下淬火态的力学性能，发现两的力学性能基本一致，同时测得其有序度以及Ｂ在晶界的偏聚随淬火温度的变化趋势，分析认为，Ｎｉ３Ａｌ－Ｂ合金的中温脆性并非由于Ｂ在高温下偏聚消失所致，Ｂ在Ｎｉ３Ａｌ晶界的偏聚属平衡偏聚。     

稀土元素铈对铸态Al-Mg合金组织和力学性能的影响

通过对比试验,利用拉伸力学性能测试、金相显微镜、扫描电镜(SEM)、能谱分析(EDS)、XRD衍射等手段研究稀土元素铈不同添加量对铸态Al-Mg合金组织的影响。结果表明,添加铈使铸态Al-Mg合金晶粒得到细化,枝晶尺寸明显减小。当铈的添加量为0.3%时,铸态Al-Mg合金具有良好的综合性能。     

China rare earth market review

正November 1~10,2014Chinese rare earth market was still inactive.Demand for rare earth products was weak.Consumers took a wait-and-see attitude for lower price.As it was an off season for rare earth products,it was expected that prices of rare earth could continue turbulence at the bottom in short terms.Due to a sharp drop,demand for rare earth from downstream recovered.Affected by new energy vehicles,wind powder and energy-efficient appliances,production of rare earth permanent     

China rare earth market review

正August 1~10,2014 There was some good news in rare earth industry recently.Restructuring plans of rare earth groups led by Baotou IronSteel Group and Xiamen Tungsten Group respectively have been approved by MIIT.And rare earth storage policy,which had been expected for a very long time,has been launched officially.Pushed by the good news,rare earth price started to rebound since August 5.Price of didymium oxide and dysprosium oxide rose about 1% to 2%,averagely.About 10% of     

China rare earth market review

正July 1~10,2014Due to weak demand from downstream industry and slow transactions,rare earth market remained weak and price of rare earth products continued to decline.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,     

New energy vehicle:an opportunity for rare earth magnets

<正>Extracted from Securities Guide 1.Popularity of new energy vehicles—an irresistible market trend1.1 Progress of new energy vehicles Chinese Premier Li Keqiang said recently on a visit to Xi'an BYD Autos that new energy vehicles,especially new energy bus,can lessen environment and noise pollution.He encouraged the use of new     

注浆加固技术在十三矿-685 m进风大巷中的应用

针对煤矿开采深度不断向深部延伸,掘进巷道受深部高应力的影响越来越大,巷道围岩整体稳定性差,矿山压力显现越剧烈现象,一般锚网喷加锚索支护无法从根本上控制巷道的变形。总结了平煤股份十三矿-685 m进风大巷注浆加固技术,依据对巷道掘进之后变形监测数据的采集,对巷道变形机理进行分析研究,并对注浆时段进行了合理选择,在对巷道的注浆工艺进行了充分论证的基础上,对巷道进行了注浆。注浆后效果表明:巷道滞后注浆时间段的选择非常重要,巷道在恰当的时间内进行注浆加固施工,能有效控制巷道的变形,巷道注浆后变形量明显减小,岩体的稳定性明显增强,减少了巷道日常维修工作,降低了矿井的生产成本,保障了矿井的安全生产。     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel