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  • Volume 36,Issue 8,2007 Table of Contents
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    • >材料科學(xué)
    • Nodular Corrosion Resistance of Zr-Sn-Nb Alloy

      2007, 36(8):1317-1321.

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      Abstract:把N18(NZ2)鋯合金樣品經(jīng)過(guò)多種不同的熱處理后,用高壓釜在500℃,10.3MPa過(guò)熱蒸汽中進(jìn)行腐蝕試驗(yàn),研究了它們的耐癤狀腐蝕性能。結(jié)果表明:無(wú)論是將樣品加熱到β相,α+β雙相還是α相后,快冷還是緩冷,它們經(jīng)過(guò)1100h腐蝕后都沒(méi)有出現(xiàn)癤狀腐蝕。說(shuō)明在Zr-Sn合金中再添加合金元素Nb后,對(duì)癤狀腐蝕產(chǎn)生了“免疫性”。樣品在500℃過(guò)熱蒸汽中的腐蝕增重動(dòng)力學(xué)曲線仍可分為兩個(gè)階段,轉(zhuǎn)折發(fā)生在氧化膜厚度大約為3μm時(shí)。

    • Stress Distribution near Crack Tip for Beryllium Specimen under Compact Tension

      2007, 36(8):1322-1325.

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      Abstract:為了評(píng)估應(yīng)力作用下鈹試樣裂紋尖端的微觀斷裂特性,設(shè)計(jì)了平面應(yīng)變狀態(tài)下鈹?shù)木o湊拉伸試樣,采用X3000應(yīng)力分析儀測(cè)試了不同載荷下鈹試樣裂紋尖端的應(yīng)力分布,并對(duì)加載過(guò)程中鈹試樣內(nèi)的應(yīng)力應(yīng)變進(jìn)行了有限元計(jì)算。結(jié)果表明,離鈹試樣裂尖較遠(yuǎn)區(qū)域,有限元計(jì)算和實(shí)測(cè)值吻合較好,靠近裂尖區(qū)域,有限元計(jì)算高于實(shí)測(cè)值。根據(jù)鈹試樣拉伸時(shí)裂紋擴(kuò)展的臨界載荷,計(jì)算獲得了鈹試樣裂紋尖端的最大應(yīng)力、塑性區(qū)半徑以及斷裂強(qiáng)度因子。

    • Characteristics of Oxidation Film on Ignition-proof Mg-3.5Y-0.8Ca Alloys at High Temperatures

      2007, 36(8):1326-1330.

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      Abstract:A magnesium alloy with excellent ignition-proof property was acquired by adding yttrium and calcium at the same time. The Mg-3.SY-0.8Ca alloy could be immune from ignition at 1173 K for 30 min. XRD, SEM and AES analysis of oxide scale revealed that the oxide film formed on the surface of Mg-3.SY-0.SCa alloy was mainly composed of Y2O3. The Y2O3 film may be considered as an outstanding protective film due to its stable crystal structure, high melting point, low steam pressure, the P-B ratio more than 1, compact structure, low conductivity and excellent ductibility and so on.

    • Influence of Heterogeneous Microstructure on the Plastic Behavior of Single Crystal Dual Phase Ni-base Superalloy

      2007, 36(8):1331-1335.

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      Abstract:A theory of crystal plasticity including back stress and damage evolutions has been established in this paper. The effects of strain rate on the matrix and precipitate phases of Ni-base superalloy have been analyzed using the theory. The computational result revealed that the both matrix and precipitate phases were seriously affected by strain rate. The nonuniform microcosmic stresses and plastic slips were induced by the microcosmic heterogeneity of single crystal dual phase alloy. The microcosmic plastic slips originate in matrix firstly. The heterogeneity of microcosmic stresses and plastic slips is probably the origin of the damage evolution and the nucleation of micro voids.

    • Effect of Microelements on the Microstructural Evolution of Al-Ag Alloys during Initial Aging Stage by Kinetic Monte Carlo Model

      2007, 36(8):1336-1340.

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      Abstract:采用基于Multi-States Ising Model的Kinetic Monte Carlo算法,模擬研究了添加微量元素對(duì)Al-Ag合金時(shí)效初期微觀結(jié)構(gòu)的演變過(guò)程的影響。結(jié)果表明:在Al-Ag合金中,In,Sn,Be元素顯著地抑制了合金時(shí)效初期的Ag原子偏聚,這是這些元素的原子與空位強(qiáng)烈地相互作用的結(jié)果。Mg元素對(duì)Ag原子的偏聚的抑制次之,添加Mg元素的合金,時(shí)效過(guò)程中出現(xiàn)了Mg-Ag原子團(tuán)簇和Ag-Mg-Va團(tuán)簇,Mg-Ag之間以及Mg-Va之間的共同作用影響了Ag原子的偏聚。Li,Cd原子與Ag原子和空位均無(wú)明顯作用,因此Li和Cd元素對(duì)時(shí)效早期Ag原子的團(tuán)聚影響較小。微量元素是通過(guò)與構(gòu)成析出相的主要溶質(zhì)元素以及空位的相互作用來(lái)實(shí)現(xiàn)對(duì)原子偏聚過(guò)程的影響,進(jìn)而來(lái)影響Al-Ag合金的時(shí)效過(guò)程的,其中微量元素與空位的相互作用起到關(guān)鍵的作用。鎖定單空位和空位團(tuán)聚進(jìn)而降低空位可動(dòng)性是影響Al-Ag合金時(shí)效過(guò)程的兩種重要機(jī)制。

    • Precipitation and Coarsening of Coherent and Ordered Second Phase during Stress Aging by Using Phase-Filed Simulations

      2007, 36(8):1341-1345.

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      Abstract:采用雙場(chǎng)耦合條件下的宏觀相場(chǎng)法,實(shí)現(xiàn)了模擬外加應(yīng)力下無(wú)序基體中共格有序第二相的析出和粗化。結(jié)果發(fā)現(xiàn),在外加應(yīng)力下,第二相顆粒將發(fā)生定向粗化,形成筏狀組織,成筏的方向取決于外加應(yīng)力的性質(zhì)、點(diǎn)陣錯(cuò)配的正負(fù)以及兩相的彈性模量差。沉淀體積分?jǐn)?shù)越大,顆粒合并和反相疇界對(duì)沉淀形貌的影響越顯著,導(dǎo)致許多顆粒呈現(xiàn)不規(guī)則形貌。顆粒的對(duì)齊有兩種機(jī)制,一是鏈條外顆粒的溶解,一是顆粒的遷移。在粗化過(guò)程中,多顆粒體系首先通過(guò)前1種機(jī)制形成鏈條,然后通過(guò)第2種機(jī)制使鏈條進(jìn)一步對(duì)齊。

    • Influence of Low Frequency Pulsed Current Annealing on the Giant Magneto Impedance of CoFeSiB Amorphous Ribbon

      2007, 36(8):1346-1349.

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      Abstract:研究了經(jīng)不同低頻脈沖電流密度退火的Co66.3Fe3.7Si12B18非晶薄帶的巨磁阻抗(GMI)效應(yīng)。結(jié)果表明,在低頻脈沖電流下,巨磁阻抗效應(yīng)的大小與退火電流密度密切相關(guān)。非晶帶的GMI變化率△Z/Z先隨退火電流密度的增加而增強(qiáng),當(dāng)電流密度為104A/mm^2時(shí),△Z/Z達(dá)到最大值53.8%,此后隨電流密度增大,GMI變化率開(kāi)始減小。對(duì)脈沖電流退火影響巨磁阻抗效應(yīng)的機(jī)制作了定性分析。并分析了由脈沖電流退火在材料內(nèi)感生的橫向各向異性場(chǎng)鳳對(duì)GMI效應(yīng)的影響,發(fā)現(xiàn)HK有利于提高GMI效應(yīng)的峰值,但同時(shí)存在一個(gè)臨界值,當(dāng)超過(guò)這個(gè)值時(shí),GMI效應(yīng)的峰值減弱。

    • Numerical Simulation on Temperature Field in Ta/Ta-16MnR Argon-arc Welder Joint

      2007, 36(8):1350-1353.

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      Abstract:利用ANSYS軟件對(duì)用鉭制換熱管、Ta/16MnR制管板的管板式換熱器中氬弧焊接接頭進(jìn)行了數(shù)值模擬,得到了4種尺寸組合焊接接頭的溫度場(chǎng)數(shù)值模擬結(jié)果。通過(guò)對(duì)模擬結(jié)果分析,表明鉭-鋼復(fù)合板的鉭層厚度是影響焊接質(zhì)量的主要因素。為了使鉭.鋼復(fù)合板鋼層在焊接過(guò)程中不出現(xiàn)熔化,鉭層厚度要達(dá)到2.5mm。這一模擬結(jié)果通過(guò)文獻(xiàn)中的實(shí)驗(yàn)結(jié)果得到了驗(yàn)證。

    • The Change of Residual Resistance of Different Purity Beryllium after Heat Treatment

      2007, 36(8):1354-1357.

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      Abstract:運(yùn)用測(cè)量剩余電阻的方法,研究了4.2K溫度時(shí)不同純度的鈹中剩余相的分解與其溶解動(dòng)力學(xué)。結(jié)果表明:時(shí)效有效溫度取決于金屬中含有雜質(zhì)的數(shù)量,隨雜質(zhì)數(shù)量的增加而提高;高純度鈹(~99.94%)如微合金一樣也具有時(shí)效傾向;應(yīng)用剩余電阻概念研究純鈹內(nèi)部結(jié)構(gòu)轉(zhuǎn)變是非常有效的方法,它可記錄時(shí)效過(guò)程初始階段的變化(如400℃鈹中擴(kuò)散分解),這些變化用微觀觀察或X射線衍射分析很難得到。

    • Spin Transport Properties of the Thin Film Doped with La0.85Sr0.015MnO3

      2007, 36(8):1362-1365.

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      Abstract:采用磁控濺射方法制備了二價(jià)堿土元素微量摻雜錳氧化物L(fēng)a0.85Sr0.015MnO3(LSMO)薄膜。電阻-溫度關(guān)系表明,薄膜在273K時(shí)發(fā)生鐵磁金屬-順磁半導(dǎo)體相變。在磁場(chǎng)和激光作用下,薄膜呈現(xiàn)出不同的響應(yīng)特性:在整個(gè)測(cè)試溫度區(qū)間內(nèi),磁場(chǎng)作用使薄膜電阻變小,在243K時(shí),取得最大磁電阻變化率為21%;激光輻照薄膜在不同的相態(tài)顯示出不同的變化特性,在鐵磁金屬態(tài)導(dǎo)致電阻增大,而在順磁半導(dǎo)體態(tài)則致使電阻減小。從能帶理論的角度定性地分析了產(chǎn)生該現(xiàn)象的原因是外場(chǎng)對(duì)eg電子的作用不同。

    • Physical and Electrochemical Properties of Ladoped Lithium Iron Phosphate Electrodes

      2007, 36(8):1366-1368.

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      Abstract:利用固相法合成了鑭離子摻雜的Li1-xLaxFePO4正極材料,采用XRD,SEM和充放電性能表征了材料的晶體結(jié)構(gòu)、微觀形貌和電化學(xué)性能。研究表明,少量La^3+的摻雜未影響到LiFePO4的晶體結(jié)構(gòu),但顯著改變了粉體的微觀形貌,降低顆粒粒度至納米級(jí),改善了可逆容量和循環(huán)性能。得到的最佳配比正極材料Li0.99La0.01FePO4,在C/20的充放電速率下,其初始可逆放電容量達(dá)到理論容量的73%——123mAh/g,20次充放電循環(huán)后表現(xiàn)出良好的容量可循環(huán)性,容量沒(méi)有衰減。引入稀土離子是提高磷酸鐵鋰新型鋰離子正極材料電化學(xué)性能的有效方法。

    • Study on Preparation and Dielectric Properties of Nano-Ag/Epoxy Resin Composite

      2007, 36(8):1369-1372.

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      Abstract:采用紫外輻照還原的方法制備了納米銀粒子,研究了保護(hù)劑的添加、輻照強(qiáng)度和溶液配比等因素對(duì)納米銀粒子尺寸的影響。TEM反映出銀粒子分散均勻,其粒度約為20nm。將制備出的納米銀與環(huán)氧樹(shù)脂混合固化形成納米復(fù)合電介質(zhì),研究了這種復(fù)合材料的介電性能:室溫下復(fù)合材料的體積電阻率和工頻擊穿場(chǎng)強(qiáng)隨著納米銀粒子的加入有所提高,介質(zhì)損耗略有降低,而介電常數(shù)變化不大。結(jié)果表明,納米銀粒子能夠提高基體聚合物的介電性能。這一現(xiàn)象可用庫(kù)侖阻塞機(jī)制解釋。

    • Fabrication of Cd0.9Zn0.1Te:In by Thermal Annealing Technology under Controlled Indium Vapor

      2007, 36(8):1373-1376.

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      Abstract:利用控制In氣氛下的熱處理工藝成功地制備了CdZnTe:In。不同In壓下(Cd,Zn分壓保持在平衡分壓)的熱處理實(shí)驗(yàn)結(jié)果表明:熱處理后樣品的電阻率可從6.75×10^5Ω·cm提高到10^8~10^1010Ω·cm;并且隨著In壓的增加,導(dǎo)電類型逐漸由p型轉(zhuǎn)變?yōu)閚型。熱處理后樣品的電阻率變化特征可以由In的擴(kuò)散和施主缺陷InCd、受主缺陷VCd之間的補(bǔ)償作用來(lái)很好地解釋。利用擴(kuò)散理論建立了CdZnTe:In的電阻率物理模型。利用熱處理后樣品的電阻率數(shù)據(jù),計(jì)算了在873,973和1073K時(shí)In原子在CZT晶體中的有效擴(kuò)散系數(shù)DIn,分別為3.455×10^-11,2.625×10^-10和5.17×10^-9cm^2/s。將擴(kuò)散數(shù)據(jù)經(jīng)過(guò)擬合后得到了DIn的表達(dá)式:1.35exp(-1.85eV/kT)cm^2/s(873~1073K)。

    • Electric Polarized Post Treatment of Plasma Sprayed Hydroxyapatite Coatings in Alkaline Solution

      2007, 36(8):1377-1381.

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      Abstract:采用堿液環(huán)境中電極化處理法(PAS)和水蒸氣處理法(wVT)對(duì)等離子噴涂羥基磷灰石涂層進(jìn)行后處理。采用XRD,F(xiàn)TIR,SEM,接觸角測(cè)量?jī)x等測(cè)試手段對(duì)涂層進(jìn)行表征。結(jié)果表明,PAS和WVT都能提高涂層的結(jié)晶度和結(jié)構(gòu)完整性,促使涂層中的雜相向羥基磷灰石轉(zhuǎn)化,但PAS比WVT轉(zhuǎn)化得更完全。PAS與WVT兩種后處理方法對(duì)涂層原有的表面形貌影響都不大。與WVT相比,PAS處理后的涂層親水性更好、表面能更高,且涂層表面上產(chǎn)生了更多的負(fù)電荷。PAS處理后的涂層與基體材料的結(jié)合強(qiáng)度略低于WVT,但仍然達(dá)到了ISO13779-2:2000標(biāo)準(zhǔn)的相關(guān)要求。

    • Synthesis and Electrochemical Properties of LiMn2O4 Cathode Material

      2007, 36(8):1382-1385.

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      Abstract:根據(jù)Li2CO3/MnO2混合粉體的TG-DSC分析結(jié)果,采用高溫固相反應(yīng)法,在不同的預(yù)保溫溫度下合成出正極材料LiMn2O4。對(duì)其進(jìn)行XRD,SEM表征和電化學(xué)性能測(cè)試,確定了在600℃預(yù)保溫和830℃最終合成的優(yōu)化工藝。該工藝合成的LiMn2O4粉體具有單一的尖晶石相結(jié)構(gòu)和粒度分布均勻的形貌。組裝成電池在常溫下循環(huán)時(shí),初始放電比容量達(dá)122mAh/g,20次循環(huán)后容量保持在96%左右。其循環(huán)伏安曲線經(jīng)過(guò)20次循環(huán)后仍可保持較好的形狀。

    • Monolayer NiAI Composite Reinforced with Mo fibers by Plasma Spray

      2007, 36(8):1386-1389.

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      Abstract:采用等離子噴涂工藝,制備了Mo絲增強(qiáng)的NiAl基單層復(fù)合材料。系統(tǒng)地研究了該復(fù)合材料的顯微組織,Mo絲/NiAl界面的結(jié)合特性以及在不同熱處理狀態(tài)下復(fù)合材料的界面行為。研究表明:制備態(tài)單層復(fù)合材料的基體由強(qiáng)烈變形(扁平化)和高速結(jié)晶的NiAl熔滴顆粒形成的層狀結(jié)構(gòu)構(gòu)成,顆粒間有較多的分界面,Mo絲/基體的界面結(jié)合強(qiáng)度不高,其結(jié)合為非冶金結(jié)合。800℃,3h退火后,Mo絲/基體界面的結(jié)合情況得到改善,復(fù)合材料的性能提高。更高溫長(zhǎng)時(shí)處理后,基體元素Ni在Mo絲中形成擴(kuò)散層,在界面處基體一側(cè)和基體中結(jié)晶的熔滴顆粒分界面處的鋁的氧化物層明顯增厚。

    • Interfacial Characteristics and Mechanical Properties of W Fiber Reinforced ZrTiCuNiBe Amorphous Matrix Composite

      2007, 36(8):1390-1393.

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      Abstract:The W fiber reinforced Zr41.25Ti13.75Cu12.sNi10Be22.5 amorphous matrix composites with 50 mm in length and 6 mm in diameter have been produced by the melt infiltration casting method. The interface reaction appearance of the composite was analyzed by scanning electron microscopy at the same infiltration time and different infiltration temperatures. The interfacial shear strength of composite is determined by the push-out method. The relations between the macroscopically compressive fracture behaviors with the interracial characteristics and shear strength are discussed in the end. The results indicate that the plastic behaviors and fracture toughness of amorphous alloy were improved obviously, the interracial combination of composites included the two processes of interface diffusion and interface reaction, and the interracial shear strength increased when the interface reaction was pricked up. At the same time, the compressive failure mode of composite changed from the longitudinal split to the single shear failure.

    • Porous Titanium by Fiber Sintering and Its Biomimetic Ca-P Coating

      2007, 36(8):1394-1397.

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      Abstract:采用鈦纖維燒結(jié)法制備了多孔鈦,并應(yīng)用混合堿-熱處理對(duì)其表面進(jìn)行活化處理,然后在過(guò)飽和鈣磷溶液中進(jìn)行表面鈣磷涂覆。測(cè)試了多孔鈦的壓縮性能,分析了涂層的形貌、元素含量和相組成。結(jié)果表明,制備的多孔鈦為三維貫通結(jié)構(gòu),孔隙度在29%~84%,孔隙尺寸為100~800gm。當(dāng)孔隙度為55%~60%時(shí),壓縮屈服強(qiáng)度為150~230MPa,彈性模量為4.0~4.2GPa,與骨組織相近。經(jīng)表面鈣磷涂覆處理的多孔鈦在模擬體液中浸泡3天后,內(nèi)外孔壁均被類骨磷灰石覆蓋,表現(xiàn)出良好的誘導(dǎo)骨生長(zhǎng)特性。

    • Effect of Electroless Deposition on the Corrosion Resistance Property for NdFeB Permanent Magnets with Surface Coating of Ni-P Alloy

      2007, 36(8):1398-1402.

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      Abstract:The coating technics by electroless deposition with Ni-P alloy on the surface of NdFeB magnets were optimized by orthogonal experiments. The microstructure and morphology of NdFeB magnets with electroless Ni-P deposit from an acidic bath and an alkaline bath were studied and compared. The corrosion rates of Ni-P deposites and substrate were measured in the NaCl solutions of 3.5wt%, the HCl solutions of 10vot% and the NaOH solutions of 20wt%. The corrosion characteristics of Ni-P deposits were evaluated for the two baths by electrochemical potentiodynamic polarization and impedance techniques. The results show that both deposits enhanced the corrosion resistance of substrate. The Ni-P deposit from the acidic bath provides a better protection due to the amorphous structure, and the continuous and compact cystiform microstructure on the surface of coatings.

    • Electrochemical Properties of SnSb Alloy Anode Materials Synthesized by Carbothermal Reduction

      2007, 36(8):1403-1406.

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      Abstract:Anode materials of microcrystalline spherical SnSb alloy for lithium-ion batteries were synthesized from tin and antimony oxides by carbothermal reduction. The so-prepared electrode shows a low initial irreversible capacity and good cycling performance. The initial capacity loss and reversible capacities are 160 mAh/g and 650 mAh/g, respectively. The relatively low specific surface area of SnSb particles should be responsible for the low initial irreversible capacity, while the polycrystalline characteristics of SnSb particles is apparently favorable for the improvement of cyclieability of SnSb electrode. The electrochemical reaction process of SnSb alloy electrode was characterized by cyclic voltammetry and AC impedance techniques.

    • Isothermal Oxidation Behavior of Single-Crystal Ni-Base Superalloy Containing Rhenium in Air

      2007, 36(8):1407-1411.

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      Abstract:采用X射線衍射(XRD),掃描電鏡(SEM)及能譜(EDAX)等手段,研究了含錸單晶高溫合金DD32的高溫氧化行為。結(jié)果表明,氧化初期增重迅速,由NiO的形成和生長(zhǎng)控制,符合拋物線規(guī)律;隨著氧化時(shí)間的延長(zhǎng),氧化增重變得十分緩慢,由α-Al2O3的形成和生長(zhǎng)控制。在900,1000℃時(shí)的氧化膜由3層組成,最外層為(Ni,Co)O層,中間層由復(fù)雜化合物以及尖晶石化合物等組成,內(nèi)層為靠近基體合金的連續(xù)的Al2O3層。氧化過(guò)程中,分布在中間層的富Re和W相起到“擴(kuò)散障”的作用,降低基體合金中Al向外的擴(kuò)散速率,在內(nèi)層形成均勻連續(xù)的Al2O,氧化膜層,進(jìn)而抑制氧化膜生長(zhǎng),導(dǎo)致氧化速率降低。

    • Evaluation Methods on Adhesion Property of Metallic Films

      2007, 36(8):1412-1415.

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      Abstract:The adhesion property of Au/NiCr/Ta multi-layered metallic films was investigated by the indentation method, rolling contact fatigue method and scratch method with both friction and acoustic emission modes. The results indicate that the indentation method can not distinguish if the failure happens between the metallic film and substrate and there are no cracks during the indentation process; and the rolling contact fatigue method can not be used to evaluate the adhesion property for metallic films due to the plastic deformation; only the scratch method can eventually be used to distinguish the special scratch behavior for multi-layered metallic films. Additionally, the friction mode can reflect the changes on different metallic film layers, it is more sensitive than the acoustic emission in the same layer. The number of layers and the layer thickness of film and the scratch resistance of metallic films can be reflected by a critical characteristic load at a certain extent.

    • Morphologies and Microstructures of Ag5Fe Powders Produced by Ultrasonic Arc Gas Atomization

      2007, 36(8):1416-1419.

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      Abstract:利用超音速氣霧化的方法制備了液態(tài)微溶、固態(tài)不互溶的Ag5Fe粉末。利用電弧在放電時(shí)的高溫使Fe熔解于Ag中,在隨后的快速凝固過(guò)程中形成含有亞穩(wěn)合金相的Ag5Fe粉末。掃描電鏡觀察顯示:Ag5Fe粉末的粒度較均勻、細(xì)小,呈正態(tài)分布,大部分集中在25-55μm;取典型顆粒放大處理后發(fā)現(xiàn):顆粒的富Ag基體中高度彌散分布著粒度在納米級(jí)的Fe相,在富Fe基體中亦有粒度為納米級(jí)的彌散分布的Ag相。計(jì)算結(jié)果表明:經(jīng)超音速氣霧化之后Ag-Fe合金顆粒有固溶,且粉末顆粒越細(xì)小固溶擴(kuò)展越大。Fe在富銀區(qū)域中的固溶度亞穩(wěn)擴(kuò)展至0-3at%~0.6at%;且在忽略少數(shù)粒度較大的粉末顆粒條件下,粉末顆粒越細(xì),亞穩(wěn)固溶度越大。

    • Effects of Rare Earth Nd on Microstructure and Mechanical Properties of Laser Rapid Formed TC4 Titanium Alloy

      2007, 36(8):1420-1424.

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      Abstract:針對(duì)氫化脫氫鈦合金粉末氧含量較高的問(wèn)題,研究了添加稀土釹對(duì)激光快速成形TC4合金組織及性能的影響。結(jié)果發(fā)現(xiàn),添加稀土Nd后,激光快速成形TC4合金的宏觀晶粒尺寸變化不大;但隨稀土添加量的增加,初始β列狀晶逐漸轉(zhuǎn)化為全β等軸晶,晶粒內(nèi)部的魏氏α組織逐漸轉(zhuǎn)變?yōu)榫W(wǎng)籃α,粗化α條不斷增多,呈現(xiàn)團(tuán)束聚集趨勢(shì),晶界α集束體積分?jǐn)?shù)也不斷增大;隨稀土添加量的增加,激光快速成形TC4合金的室溫塑性先大幅度提高,然后急劇降低;稀土添加量為0.1%~0.2%(質(zhì)量分?jǐn)?shù),下同)時(shí),氧含量為0.26%的氫化脫氫TC4合金粉末激光快速成形件沉積態(tài)的抗拉強(qiáng)度達(dá)975MPa,延伸率9.5%,滿足鍛件標(biāo)準(zhǔn)要求。

    • Influences of Adding Trace RE Elements on the Structure and Properties of Cu-10Ag Alloy in situ Fiber Composites

      2007, 36(8):1425-1430.

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      Abstract:制備了Cu-10Ag和Cu-10Ag-RE(RE=Ce,Y,Gd)合金原位纖維復(fù)合材料,研究了它們的顯微結(jié)構(gòu)與性能。結(jié)果表明,微量RE添加劑對(duì)合金鑄態(tài)組織具有變質(zhì)和細(xì)化作用,增大了(Cu+Ag)共晶比例和減少了Ag沉淀比例,并能提高合金的再結(jié)晶溫度和不連續(xù)Ag沉淀溫度。隨真實(shí)應(yīng)變叩增大,復(fù)合材料中Ag纖維平均直徑d呈η的負(fù)指數(shù)函數(shù)減?。篸=d0·exp(-0.228η),而復(fù)合材料的應(yīng)變強(qiáng)度呈η的指數(shù)函數(shù)增大:σCu/Ag=σ0(Cu)+[kCu/Agd0^-1/2]exp(η/3)。Cu-10Ag和Cu-10Ag-RE復(fù)合材料顯示兩階段強(qiáng)化機(jī)制:低應(yīng)變階段為加工硬化機(jī)制,高應(yīng)變階段為超細(xì)Ag纖維及界面強(qiáng)化機(jī)制。微量RE添加劑明顯減小兇值,因而明顯增高原位纖維復(fù)合材料的應(yīng)變強(qiáng)化速率。

    • >材料工藝
    • Effects of Rapid Quenching on the Microstructures and Electrochemical Performances of La0.7Mg0.3Ni2.55-xCo0.45Alx (x = 0

      2007, 36(8):1431-1435.

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      Abstract:用鑄造及快淬工藝制備了La-Mg-Ni系(PuNi3型)電極合金La0.7Mg0.3Ni2.55-xCo0.45Alx(x=0,0.1,0.2,0.3,0.4),研究了快淬工藝對(duì)合金微觀結(jié)構(gòu)及電化學(xué)性能的影響。XRD分析結(jié)果表明,鑄態(tài)及快淬態(tài)合金具有多相結(jié)構(gòu),包括(La,Mg)Ni3相和LaNi5相和一定量的LaNi2相,快淬處理對(duì)合金的相組成沒(méi)有影響,但使相的相對(duì)含量產(chǎn)生變化。TEM及SEM分析結(jié)果表明,快淬處理顯著改善合金的成分均勻性,使晶粒細(xì)化。Al替代Ni不利于非晶相的形成,但使快淬態(tài)合金的晶粒顯著細(xì)化。電化學(xué)測(cè)試結(jié)果表明,快淬處理顯著提高合金的循環(huán)穩(wěn)定性,但不同程度地降低合金的放電容量和活化性能,快淬對(duì)放電電壓特性的影響是復(fù)雜的。

    • Fabrication of Er3+:Y2O3 Nanocrystalline Powder of Upconversion Luminescence by Co-precipitation

      2007, 36(8):1436-1439.

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      Abstract:以Y2O3為基質(zhì)材料,摻雜不同含量的Er^3+,采用共沉淀法制備出性能良好的Er^3+:Y2O3上轉(zhuǎn)換發(fā)光納米粉。對(duì)不同溫度下煅燒后的粉體進(jìn)行了X射線衍射、能譜測(cè)試、透射電鏡和比表面積分析。結(jié)果表明:Er^3+完全固溶于Y2O3的立方晶格中,Er^3+:Y2O3粉體粒度均勻,近似球形,且隨著煅燒溫度的升高,其顆粒逐漸變大;1000℃煅燒2h的粉末尺寸為40~60nm。

    • Effect of Amorphous Carbon Doping on Microstructure and Superconducting Properties of MgB2 Bulk

      2007, 36(8):1440-1443.

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      Abstract:以無(wú)定形碳粉末作為摻雜物質(zhì),通過(guò)固相燒結(jié)的方法,在750℃,高純氬氣保護(hù)下,熱處理2h制備了MgB2-xCx(x=0,0.05,0.10,0.20,0.30)超導(dǎo)塊材。用X射線衍射(XRD)儀,掃描電子顯微鏡(SEM)和物性測(cè)試儀(PPMS)對(duì)樣品的微觀結(jié)構(gòu)和超導(dǎo)電性進(jìn)行了系統(tǒng)分析。結(jié)果顯示,在750℃熱處理?xiàng)l件下,有部分碳進(jìn)入MgB2的晶格中,其余碳處于MgB2的晶界處。少量碳摻雜可以有效細(xì)化MgB2晶粒,并改善MgB2的超導(dǎo)電性。MgB19C0.1塊材的臨界電流密度(Jc)在20K,3T條件下達(dá)到8×10^4A/cm^2,表明無(wú)定形碳摻雜可有效提高M(jìn)gB2的磁通釘扎。

    • Evaluation on Microtructures and Properties of Laser Cladding Layer for WFLC-11 Co-based Alloy

      2007, 36(8):1444-1446.

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      Abstract:對(duì)自主開(kāi)發(fā)的WFLC-11激光熔覆專用鈷基合金粉末激光熔覆層與Stellite-6合金等離子噴焊層的組織與性能進(jìn)行了比較研究。結(jié)果表明,激光熔覆層組織細(xì)小、均勻,致密性好,高溫硬度更高,其顯微硬度、耐腐蝕性能、抗擦傷性能優(yōu)于Sellite-6合金等離子噴焊層。

    • Influences of Electrolyte Parameters on the Structure and Properties of Micro-Arc Oxidation Coatings of Zicralloy

      2007, 36(8):1447-1451.

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      Abstract:研究了不同電解液參數(shù)對(duì)于Zr合金微弧氧化膜結(jié)構(gòu)和性能的影響。實(shí)驗(yàn)證明,在不同濃度的NaOH溶液中,微弧氧化反應(yīng)的擊穿電壓與陰離子濃度成反比,并且溶液的濃度不能過(guò)高或者過(guò)低。采用NaOH,Na2SiO3和Na3PO43種溶液作為電解液產(chǎn)生的微弧氧化膜,在結(jié)構(gòu)和形貌上有很大的區(qū)別。電解液中的陰離子會(huì)參與微弧氧化反應(yīng)。氧化膜中的Si元素有利于穩(wěn)定ZrO2的高溫相,并使氧化膜結(jié)構(gòu)平整、減少孔洞和裂紋,提高合金耐腐蝕性,而P元素卻有著相反的作用。

    • Influence of Preparing Conditions on the Particle Size of Indium Tin Oxide (ITO) Powders

      2007, 36(8):1452-1456.

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      Abstract:以純In,SnCl4·5H2O和鹽酸為原料,采用絡(luò)鹽法制備了納米晶銦錫氧化物(ITO)粉末。通過(guò)對(duì)銦和錫的絡(luò)合鹽——(NH4)2InCl5·H2O和(NH4)2SnCl6的制備研究,充分證實(shí)了反應(yīng)初始溶液中絡(luò)離子的存在;通過(guò)調(diào)節(jié)氯離子與銦離子的總濃度比(TCl/TIn)研究了絡(luò)離子對(duì)ITO粉末粒度的影響,還系統(tǒng)地研究了沉淀劑的濃度、終點(diǎn)pH值、前驅(qū)體洗滌次數(shù)和煅燒溫度對(duì)ITO粉末粒度的影響:通過(guò)XRD和激光粒度儀對(duì)所制粉體進(jìn)行了表征。結(jié)果表明:當(dāng)TCl/TIn=5,沉淀劑為20%的NH4HCO3溶液,終點(diǎn)pH值為6.0~7.0,前驅(qū)體的洗滌次數(shù)為6次,煅燒溫度為700~800℃時(shí)所得ITO粉末粒度最佳。

    • Fabrication of Hard/Soft Nanocomposite Magnetic Particles by Sonochemistry

      2007, 36(8):1457-1460.

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      Abstract:Sm-Fe-N/Fe and Nd-Fe-B/Fe nanocomposite magnetic powders were successfully prepared by the use of sonochemistry to decompose the carbonyl iron compounds in decane solvents containing Sm-Fe-N and Nd-Fe-B powders at low temperature and in an inert atmosphere, respectively. The TEM observations and the corresponding EDS analysis show that the small nano-iron by sonochemical process are pure with a particle size of about 5 rim. The SEM observations indicate that the Sm-Fe-N and Nd-Fe-B powders are well coated by nano-sized Fe. The content coating Fe can be easily adjusted by controlling the carbonyl iron and the related sonochemical process. In addition, the preparation conditions and mechanism of coating process were discussed.

    • Spark Plasma Sintering of ODS Cobalt Base Alloy Powder by Mechanical Alloying

      2007, 36(8):1461-1464.

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      Abstract:采用機(jī)械合金化(MA)和放電等離子燒結(jié)(SPS)技術(shù)制備了Y2O3彌散強(qiáng)化Co基合金,研究了高能球磨過(guò)程中粉末形貌和微觀結(jié)構(gòu)的變化規(guī)律以及機(jī)械合金化粉末的放電等離子燒結(jié)行為。結(jié)果表明:在球磨的初始階段(≤8h),粉末粒度和晶粒尺寸顯著減小,晶格畸變?cè)龃?;球?h以后,粉末粒度、晶粒尺寸和晶格畸變的變化漸緩;但進(jìn)一步延長(zhǎng)球磨時(shí)間,使Y2O3彌散粒子的分布更加均勻。采用放電等離子燒結(jié)技術(shù),在1100℃,10min條件下便可制備出相對(duì)密度〉99%的合金試樣,所得合金平均晶粒小于5μm,經(jīng)過(guò)均勻化熱處理后,合金的室溫抗壓強(qiáng)度和壓縮延伸率分別達(dá)到1982MPa和27%,優(yōu)于鑄造鉆基合金。

    • Influence of PEG Dispersant on the Stability of ITO Precursor Slurry

      2007, 36(8):1465-1468.

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      Abstract:以金屬銦和結(jié)晶四氯化錫為原料,加入各種添加劑制備了穩(wěn)定的ITO前驅(qū)物漿料。利用Zeta電位、掃描電鏡、沉降試驗(yàn)研究了分散劑PEG對(duì)漿料穩(wěn)定性能的影響。結(jié)果表明,分散劑PEG與ITO前驅(qū)物氫氧化物膠粒表面建立了較強(qiáng)的氫鍵,通過(guò)空間位阻穩(wěn)定作用提高了漿料的穩(wěn)定性;PEG的加入可使?jié){料中固體顆粒分散均勻,顆粒粒度主要分布在50~100nm之間;沉降試驗(yàn)和粘度的測(cè)定表明,漿料pH值在8.0,分散劑PEG用量在1.0%~2.0%(質(zhì)量分?jǐn)?shù),下同),粘度在2.1-2.6mPa·s時(shí),在沉降120h后的漿料中,固體顆粒沉降體積百分比在10%以內(nèi),能夠保證漿料的相對(duì)穩(wěn)定。

    • Microstructure and Magnetic Properties of Amorphous FeTsSi9B13 Alloy in Low Frequency Pulse Magnetic Field

      2007, 36(8):1469-1472.

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      Abstract:研究了低頻脈沖磁場(chǎng)處理對(duì)非晶合金Fe78Si9B13微觀結(jié)構(gòu)及磁性的影響。用非接觸紅外測(cè)溫儀對(duì)試樣的溫升進(jìn)行測(cè)量,用穆斯堡爾譜儀、透射電鏡等儀器對(duì)樣品的組織結(jié)構(gòu)、晶化行為進(jìn)行分析,利用交變梯度磁強(qiáng)計(jì)AGM對(duì)樣品的磁性進(jìn)行測(cè)試。結(jié)果表明,低頻脈沖磁場(chǎng)處理(脈沖頻率f=10-40Hz,磁場(chǎng)強(qiáng)度H=(100~400)×79.6A/m,處理時(shí)間t=-180-1200s)可在溫升△T≤7℃的情況下,促進(jìn)非晶合金Fe78Si9B13發(fā)生單相晶化,晶化相為α-Fe(Si),晶粒尺寸為2~10nm,析出量為3%~7%。樣品在經(jīng)過(guò)f=40Hz,H=300×79.6A/m,t=300s處理后,獲得較好磁性能:Bs=1.74T,H0=0.13×79.6A·m^-1。

    • Effect of Ce-La Mixed Rare Earth Content and Environment Conditions on the Creep Rupture Life of SnAgCu Solder Joints

      2007, 36(8):1473-1476.

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      Abstract:采用搭接面積為1mm^2的微型接頭,研究了Ce-La混合稀土(RE)含量和環(huán)境條件對(duì)Sn2.5Ag0.7CuxRE釬料釬焊接頭蠕變斷裂壽命的影響。結(jié)果表明:添加微量RE可改變釬焊接頭界面層金屬間化合物的幾何尺寸及形態(tài),從而影響SnAgCuRE釬料合金釬焊焊點(diǎn)的蠕變斷裂壽命。當(dāng)RE添加量為0.1%時(shí)(質(zhì)量分?jǐn)?shù),下同),焊點(diǎn)界面金屬間化合物尺寸小且均勻,蠕變斷裂壽命最長(zhǎng),為SnAgCu焊點(diǎn)蠕變斷裂壽命的8.4倍,其值明顯高于商用釬料Sn3.8Ag0.7Cu焊點(diǎn)的蠕變斷裂壽命。在相同條件下,焊點(diǎn)的服役溫度升高、應(yīng)力增加,將導(dǎo)致焊點(diǎn)的蠕變斷裂壽命下降。

    • Preparation and Properties of Spherical Spinel LiMn2O4 Cathode by Electrolysis at Low Temperatures

      2007, 36(8):1477-1479.

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      Abstract:采用MnSO4-H2SO4混合溶液作電解液,高純鉛板作電極,控制電解池溫度為0~10℃,低溫電解制取球形MnO2微粒;將其用一定濃度硝酸鋰溶液浸漬,經(jīng)過(guò)520℃低溫合成、760℃高溫結(jié)晶獲得球徑較為均一的球形尖晶石錳酸鋰鋰離子電池正極材料。通過(guò)XRD和SEM對(duì)其進(jìn)行了相結(jié)構(gòu)表征和表面形貌觀察。組裝試驗(yàn)電池,測(cè)得材料初始容量約為105mAh·g^-1,6次循環(huán)放電后循環(huán)過(guò)程趨于穩(wěn)定,第30次循環(huán)充電容量保持在98.1mAh·g^-1,放電容量保持在95.0mAh·g^-1,表現(xiàn)出良好的充放電循環(huán)性能。

    • Electrodeposition of Rare Earth Magnetic Funcition Alloy Nanowires in Nonaqueous System

      2007, 36(8):1480-1482.

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      Abstract:利用多孔陽(yáng)極氧化鋁模板,在尿素-NaBr-KBr-酰胺體系中電沉積稀土-鐵系金屬(La-Co)合金納米線。用掃描電子顯微鏡(SEM)觀察(La-Co)合金納米線的表面形貌,用磁振動(dòng)樣品磁強(qiáng)計(jì)(VSM)研究了LaCo合金的磁性。結(jié)果表明,納米線直徑較為均勻,且每條納米線的尺寸為70~80nm,與AAO模板的納米孔徑大小相符合:X射線衍射(XRD)分析表明,La-Co合金為L(zhǎng)aCo5晶體;在室溫下呈現(xiàn)順磁性的La,當(dāng)與Co形成合金后,飽和磁矩接近于磁性金屬Co。

    • Combustion Synthesis of Fe-Ti-C System by Electric Field Inducement:Effect of Electric Current on the Synthesis Products

      2007, 36(8):1483-1486.

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      Abstract:采用Gleeble-1500D熱模擬試驗(yàn)機(jī),利用電場(chǎng)誘導(dǎo)Fe—Ti—C體系發(fā)生燃燒合成反應(yīng),并研究了外加電流對(duì)合成產(chǎn)物的影響。對(duì)產(chǎn)物進(jìn)行了X射線衍射(XRD)和掃描電鏡(SEM)等分析。結(jié)果表明:產(chǎn)物中均存在TiC相,而少量的Fe2Ti相僅存在于特定的階段:隨著外加電流的增加,顆粒的平均尺寸也發(fā)生不同程度的減小。外加電場(chǎng)能夠促進(jìn)反應(yīng)物粒子的固相擴(kuò)散和形核長(zhǎng)大,并最終影響合成產(chǎn)物的物相組成和顆粒尺寸。

    • Age-Hardening Mechanism of Pd-Ag-Sn-In-Zn Alloy

      2007, 36(8):1487-1489.

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      Abstract:Age-hardening behaviour and the related microstructural changes were studied to elucidate the hardening mechanism of Pd-Ag-Sn-In-Zn alloy by means of hardness test, XRD, SEM. It is shown that the increase of hardness during the early stage of age-hardening is related to the formation of intermediate precipitate phase at the grain boundary. The single phase solid solution matrix and the lameUar-like precipitate phase similar to pearlite were observed at the grain boundary by SEM. The hardness is decreasing with the coarsening of the stable second phase.

    • >綜合評(píng)述
    • Research Progress in Silicon Based Anode Materials for Lithium-Ion Batteries

      2007, 36(8):1490-1494.

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      Abstract:New anode materials with high specific capacity for lithium-ion batteries have been widely studied in recent years. Silicon and / silicon based compounds have been studied as the anode materials due to their high theoretic capacity. However, the cyclic performance of the silicon based materials must needs to be improved. In this paper, the research progresses in the silicon based anode materials for Li-ion batteries are reviewed; the problems and prospects for these materials are also discussed.

    • Shape-Controlled Synthesis and Applications of Silver Nano-Particles

      2007, 36(8):1495-1499.

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      Abstract:納米金屬顆粒由于小尺寸效應(yīng)、表面效應(yīng)、量子尺寸效應(yīng)顯示出與塊體材料不同的熱、光、電、磁、催化等性能。納米金屬材料的性能不僅與粒子尺寸有關(guān),而且還受到粒子形貌的影響。近年來(lái),金屬納米粒子的形狀控制合成受到了特別的關(guān)注。本文著重評(píng)述近年來(lái)金屬納米粒子形狀控制合成的方法并以銀為例介紹了其形狀控制合成的最新研究進(jìn)展。

    • The Optimization Research Developments of Grain Boundary Character Distribution (GBCD) of Polycrystalline Metal Materials

      2007, 36(8):1500-1504.

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      Abstract:總結(jié)了基于退火孿晶的金屬材料晶界特征分布(GBCD)優(yōu)化研究進(jìn)展,并重點(diǎn)討論了退火孿晶誘發(fā)GBCD優(yōu)化的“∑3再激發(fā)”模型、“高∑-CSL晶界分解反應(yīng)”模型和“非共格∑3晶界遷移與反應(yīng)”模型。指出“非共格∑3晶界的遷移與反應(yīng)”應(yīng)是基于退火孿晶的中低層錯(cuò)能金屬材料GBCD優(yōu)化的微觀機(jī)制;進(jìn)一步研究非共格∑3晶界的成因及其在GBCD優(yōu)化過(guò)程中的行為是十分必要的。

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