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Abstract:Titanium carbide particle reinforced tungsten matrix (TiC p/W) composites were fabricated using a hot pressing technique The effects of temperature and TiC p content on the thermophysical properties of the composites have been investigated The results show that as temperature increases, specific heat and coefficient of thermal expansion increase monotonically, thermal diffusivity decreases slightly, and thermal conductivity increases gradually The specific heat and the coefficient of thermal expansion of TiC p/W composites increase with increasing TiC p content, according to the mixture ruler The thermal diffusivity and conductivity of TiC p/W composites, which are sensitive to microstructure, decrease greatly with increasing TiC p content The experimental values of the thermal conductivity are considerably lower than the theoretical ones as result of diffraction from defects such as grain boundary and pores in the thermal conducting particles

Abstract:研究了通過 sol- gel工藝在普通玻璃表面制備均勻透明的摻銀銳鈦礦型 Ti O2 光催化復(fù)合薄膜。研究表明 :Ti O2 復(fù)合薄膜由 Ti O2 球形顆粒組成 ,其顆粒大小在 5 0 nm～ 10 0 nm;薄膜的厚度每鍍一次增加約 0 .0 9μm;薄膜中出現(xiàn)的銳鈦礦在 (10 1)面具有一定的擇優(yōu)取向。甲基橙水溶液的光催化降解實(shí)驗(yàn)表明 :摻銀 Ti O2 復(fù)合薄膜的表觀降解速率常數(shù)明顯高于未摻銀 Ti O2 薄膜的表觀降解速率常數(shù) ,這為進(jìn)一步提高 Ti O2 薄膜的光催化活性開辟了新的途徑。

Abstract:在磷酸系晶型控制劑的作用下 ,通過氫氧化鈣懸濁液的非均相沉淀法合成了文石型晶須 ,研究了在此方法中晶型控制劑、溫度以及初始 p H值等工藝因素對(duì)文石生長的影響規(guī)律。利用粉末 X射線衍射分析了所合成樣品中文石的含量 ,同時(shí)用掃描電鏡 (SEM)觀察了合成晶須的形貌狀態(tài)。經(jīng)過實(shí)驗(yàn)發(fā)現(xiàn) ,當(dāng)在氫氧化鈣懸濁液中添加磷酸系晶型控制劑后 ,體系具有類似的碳酸化過程 ,但是當(dāng)采用磷酸或酸性的磷酸鹽作為控制劑時(shí) ,作用要優(yōu)于堿性磷酸鹽 ,所獲得的樣品中文石的含量明顯較高。適合于文石生長的溫度范圍為 2 98K～ 348K,初始酸度值范圍為 8.6～ 12 .4。通過研究鎂離子與磷酸根離子對(duì)文石生長的協(xié)同作用后發(fā)現(xiàn) ,鎂離子對(duì)文石晶體的生長作用明顯優(yōu)于磷酸根 ,當(dāng)它們同時(shí)存在于溶液中時(shí) ,鎂離子的作用可以掩蓋磷酸根離子的作用。

Abstract:Li 4SiO 4 x Eu 2O 3( x =0 00 to 0 15) ionic conductors were prepared by a Sol Gel method. Structure, shape, and ionic conductivity have been studied using DTA TG, XRD, TEM and AC impedance techniques. The experimental results show that Li 4SiO 4 can be synthesised at low temperatures using the sol gel method, and that its ionic conductivity is higher than that of the sample prepared by solid state reaction. Suitable Eu 2O 3 doping improves ionic conductivity of Li 4SiO 4.

Abstract:通過保持一定釬焊溫度 ,改變釬焊時(shí)間得到不同反應(yīng)層厚度的 Al2 O3/Ag Cu Ti界面。結(jié)合掃描電鏡 (SEM)和力學(xué)試驗(yàn)結(jié)果 ,分析了反應(yīng)層厚度對(duì) Al2 O3/Ag Cu Ti/Ti- 6 Al- 4V接頭強(qiáng)度的影響。結(jié)果表明 :厚度為 1.5μm時(shí) ,接頭強(qiáng)度達(dá)到最大值 12 5 MPa;厚度小于 1μm,剪切試樣沿反應(yīng)層和 Al2 O3陶瓷界面斷裂 ;大于 3μm,沿反應(yīng)層斷裂。反應(yīng)層厚度較薄時(shí) ,接頭強(qiáng)度取決于界面強(qiáng)度和殘余應(yīng)力的大小 ;反應(yīng)層厚度較厚時(shí) ,接頭強(qiáng)度取決于反應(yīng)層自身強(qiáng)度和殘余應(yīng)力的大小。

Abstract:利用 SEM,TEM對(duì) Ti C粒子增強(qiáng)的鈦基復(fù)合材料的強(qiáng)化方式進(jìn)行研究 ,得出 :當(dāng)反應(yīng)界面厚度控制在 0 .5μm～ 2 μm時(shí) ,界面將起到良好的傳遞載荷的作用 ,使粒子承載。當(dāng)粒子的粒度較小 (d P<1μm) ,Orowan強(qiáng)化機(jī)制將參與材料強(qiáng)化 ,而當(dāng)粒子較大時(shí) (d P>1μm) ,阻礙位錯(cuò)滑移。由于兩相之間的不均勻變形 ,在界面形成較高的應(yīng)力集中 ,阻礙形變 ,并可產(chǎn)生形變位錯(cuò)源 ,使基體中位錯(cuò)增殖 ,形成位錯(cuò)胞 ,強(qiáng)化基體。當(dāng)擴(kuò)展裂紋遇到 Ti C粒子 ,使擴(kuò)展路徑發(fā)生偏轉(zhuǎn) ,增加裂紋擴(kuò)展能量 ,提高了材料的強(qiáng)度。

Abstract:Laser rapid prototyping based on metallic powders is a new manufacturing technology, which combines with computer aided design, laser cladding and rapid prototyping. The deposition mechanism, deposition system as well as the newest advance in this technology are presented. Some prospects are also predicted.

Abstract:The developmental history and application of magnetostrictive materials are introduced. Their characteristics are compared with those of Pb(Zr,Ti)O 3 piezoelectric (PZT) ceramics. The results of some research on ultraprecise micromoving actuators and optical fiber magnetoelastic sensors conducted in our laboratory are presented. Future applications of these materials are also discussed.

Abstract:The electric properties, magnetic properties, phase structure and surface conditions of various kinds of austenitic stainless steel fibres are studied, and compared with those of stainless steel bulk. The experimental results may provide a scientific basis for further improving the manufacture technique and properties of austenitic stainless steel fibres.

Abstract:Rare earth ceramics, La 0 67 Ba 0 33 Mn 1- x Fe x O 3( x =0,0 05,0 1), has been prepared. The saturation magnetization and Curie temperature decrease with increasing Fe content in the compounds La 0 67 Ba 0 33 Mn 1- x Fe x O 3,since Fe does not participate in double exchange interaction and the amount of bond Mn 3+ O 2 Mn 4+ decreases. The ferromagnetic interaction decreases with Fe doping in the compounds La 0 67 Ba 0 33 Mn 1 x Fe x O 3. Fe doping also dereases the transition temperature of the metal semiconductor transition peak and increases the resistance of La 0 67 Ba 0 33 Mn 1 x Fe x O 3. The colossal magneloresistance(CMR) effect at low temperatures has been improved for doped La 0 67 Ba 0 33 Mn 1 x Fe x O 3. The magnetoresistance ratio [ R (6T) R (0)]/ R (0) changes from 40% to 60% with increasing Fe content from x=0 to x=0 1 . The results also show that the metal semiconductor transition peak and the negative CMR effect are well described by the Dionne model.

Abstract:The mechanism of mechanical activation synthesis has been investigated in the carbothermal reduction of alumina. It was found that the experimental results can not be explained by Ren's mechanism for two phase composites. The crystal grains refining to nanometer size and microstrain producing in mechanical activation are the main reason for mechanical activation to promote carbothermal reduction of alumina.

Abstract:The AlN thin films with preferred orientation were deposited on Si(111) substrates using magnetron reactive sputtering. The effect of sputtering power on surface roughness and structure of the AlN thin films has been investigated. The experimental results indicate that as sputtering power increases, deposited rate also increases, but surface roughness and preferred orientation degree of AlN thin films become bad. Therefore, lower sputtering power should be chosen for preparing AlN thin films of good quality.

Abstract:研究了一種新型高度β合金化的阻燃鈦合金Ｔｉ４０的微觀組織。研究表明，Ｔｉ４０合金為單相β合金。其鑄態(tài)組織中存在四叉晶界及晶界周圍的白色區(qū)域，不超過７８０℃固溶處理，使其晶粒粗大、晶界寬化，晶界仍由許多小晶粒組成；８２０℃固溶發(fā)生再結(jié)晶，１１００℃固溶發(fā)生二次再結(jié)晶，大晶粒中出現(xiàn)亞晶；９５０℃鍛造，１０５０℃固溶處理后其組織為Ｓｉ－Ｏ化合物和Ｃｒ－Ｏ化合物組成的網(wǎng)狀結(jié)構(gòu)。不低于９１０℃固溶時(shí)效處理，大晶粒中出現(xiàn)了許多亞晶，使合金的室溫拉伸性能得到最佳匹配。

Abstract:在等溫變形條件下，研究了形變熱處理對(duì)Ｔｉ－１０２３合金顯微組織與力學(xué)性能的影響。結(jié)果表明：形變熱處理對(duì)Ｔｉ－１０２３合金組織細(xì)化及室溫強(qiáng)度的提高有一定的作用，但這種作用較小。此作用較小的原因與近β型Ｔｉ－１０２３合金水冷時(shí)細(xì)針狀馬氏體α′析出傾向小及等溫變形時(shí)位錯(cuò)等晶體缺陷密度較低有關(guān)。

Abstract:A near net shaped carbon fiber reinforced Al composite was prepared by a new vacuum squeeze casting process. The technology of mixing fibers and fine particles, the choice of binders, as well as the effect of a carbon coating obtained using a sol gel method are studied in this paper. The experimental results show that the fibers in the composite have a moderate volume fraction and a good distribution. The tensile strength and elastic modulus of the composite reach 900MPa and 200GPa respectively.

Abstract:The effect of trace lithium on the anti corrosion ability of industrially pure copper has been studied. The experimental results show that trace lithium can improve the anti corrosion ability of pure copper in saturated NaCl solution, but the ability decreases with increasing lithium content. The improvement in the anti corrosion property results from the effect of lithium on purification, grain size, microstructure and lattice distortion of copper. The corrosion mechanism is oxidization and electric corrosion between copper and impurities.

Abstract:采用金相、ＸＲＤ、ＳＥＭ觀察分析了Ｋｏｖａｒ合金（鐵鎳鈷合金）氧化膜的連續(xù)性、厚度對(duì)封接件的透氣率、抗拉強(qiáng)度的影響。結(jié)果表明：合金的頂氧化處理能改善玻璃與Ｋｏｖａｒ合金的封接性能，降低滲漏率，提高封接強(qiáng)度；氧化膜的連續(xù)性，致密性對(duì)封接有重要作用；具有尖晶石型結(jié)構(gòu)的氧化膜對(duì)封接有利，且氧化膜最佳增重是３ｇ／ｍ＾２～７ｇ／ｍ＾２。

Abstract:A computer controlled vacuum annealing furnace for Zr and Ti tubing is described using this system. The annealing process parameters can be measured, and optimized.