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Abstract:The mechanisms of superplastic deformation and their accommodation for TiAl based alloys are reviewed in different experimental conditions such as composition, microstructure, grain size, process parameters etc.in the present paper. The true stress-true strain relationships during superplastically deforming are also introduced and analyzed in relative detail.

Abstract:研究了低鈣磷比溶液電沉積缺鈣羥基磷灰石生物陶瓷涂層在水熱合成和700℃,800℃,900℃焙燒后的相組成和顯微組織結(jié)構(gòu);用掃描電鏡(SEM)、X射線衍射(XRD)和透射電鏡(TEM)對涂層進(jìn)行分析。結(jié)果表明:在電沉積液Ca/P比1.30,沉積液溫度25℃,電壓4V條件下,Ti基體表面沉積了片狀和條狀HAP和CaHPO4·2H2O混合相涂層;在pH值為12的堿液中,150℃和200℃水熱合成4h后涂層由針狀純HAP組成,Ca/P比約為1.61,且隨著水熱合成溫度的升高,晶體結(jié)晶度提高,但晶體無明顯長大趨勢;700℃焙燒后,涂層仍由純HAP組成,只是晶體因失水而發(fā)生團(tuán)聚;800℃焙燒后,部分HAP發(fā)生分解,生成β-Ca3(PO4)2,且HAP與β-Ca3(PO4)2的體積比為90∶10,形貌為塊狀和板條狀,其表面附著許多細(xì)小的針狀顆粒;900℃焙燒后,β-Ca3(PO4)2的含量增加,HAP與β-Ca3(PO4)2的體積比為74∶26,小顆粒團(tuán)聚成較大的塊狀和板條狀顆粒。由此制備了對骨組織生長更有利的HAP+β-Ca3(PO4)2雙相涂層結(jié)構(gòu)。

Abstract:The coercivity mechanism of HDDR anisotropic Nd Fe B magnet is investigated. The measurements of magnetization curve and different susceptibilities as well as the observations of microstructure are performed. It is concluded that the magnetic hardening of the magnet is due to the pinning of domain walls at grain boundaries and the Nd rich boundary phase that distributes homogeneously around some colonies composed of fine Nd2Fe14B grains. The coercive field is mainly determined by the pinning of domain walls by the Nd rich boundary phase. The conclusions mentioned above are in good agreement with the theoretical calculation of the intrinsic coercivity of the magnet. Furthermore, experimental verification is carried out and the processes for improving the coercivity of the magnets are proposed.

Abstract:利用高溫X射線衍射研究了純Cu，純Al，Cu75Al25，Cu71Al25Ni4(原子分?jǐn)?shù)，％)液態(tài)結(jié)構(gòu)，獲得了結(jié)構(gòu)因子。研究結(jié)果表明：純Cu和純Al熔體結(jié)構(gòu)因子主峰前曲線均呈光滑的拋物線狀；而Cu75Al25熔體的結(jié)構(gòu)因子曲線主峰前則出現(xiàn)預(yù)峰；加入Ni后，即Cu71Al25Ni4熔體的結(jié)構(gòu)因子曲線上預(yù)峰明顯增強(qiáng)。根據(jù)預(yù)峰的特性，提出兩液態(tài)結(jié)構(gòu)的原子模型，即由八面體結(jié)構(gòu)共享頂點(diǎn)形成的原子團(tuán)簇與無規(guī)密堆積原子分布區(qū)域組成。

Abstract:采用化學(xué)溶液法混料，然后用氫還原氮化法制備出具有包覆結(jié)構(gòu)的Si3N4／BN納米復(fù)合粉體，復(fù)合粉熱壓后獲得較高強(qiáng)度，同時又具有良好加工性能的復(fù)相陶瓷。掃描電鏡(SEM)，X射線衍射(XRD)分析表明：復(fù)相陶瓷中氮化硼以六方晶(h-BN)均勻分布于以α-Si3N4為基體相的晶界與晶內(nèi)，并抑制α-Si3N4的晶粒長大使基體晶粒細(xì)化。良好加工性能的獲得是由于h-BN易沿其層間解理以及h-BN與α-Si3N4兩相由于熱膨脹失配產(chǎn)生的弱界面易在剪切方向剝層所致。

Abstract:研究了以VOSO4為前驅(qū)體，應(yīng)用液相沉淀法制取VO2納米粉的制粉技術(shù)以及VO2粉末的晶化過程，采用TGA，DSC，XRD，TEM等測試手段對所得粉的物理特性進(jìn)行了測試分析。試驗(yàn)結(jié)果表明：所制取的VO2粉末顆粒粒徑介于10nm-30nm之間，該粉體經(jīng)400％真空熱處理10h可完全實(shí)現(xiàn)晶化，相變溫度為65％。

Abstract:以N2和Ar的混合氣為氣源，在Ti6Al4V表面離子滲氮形成滲氮層。對滲層的相結(jié)構(gòu)、表面粗糙度、顯微硬度及與基體的結(jié)合強(qiáng)度等進(jìn)行了測試分析，并用球-盤滑動磨損試驗(yàn)機(jī)對滲層的摩擦學(xué)性能進(jìn)行了研究。結(jié)果表明：在N2／Ar=1：1，900℃的滲氮條件下，滲氮層主要由化合物Ti2N，TiN和氮在α-Ti中的固溶體α相等相組成；滲氮后試樣的表面粗糙度增大；滲氮層的硬度較基材Ti6Al4V有很大提高，且與基體間有較好的結(jié)合強(qiáng)度；在球-盤滑動磨損試驗(yàn)中，滲氮層無減摩效果，但其耐磨性較基材Ti6Al4V大大增強(qiáng)。

Abstract:研究了TiC，TiB2兩種鈦化物在純鋁熔體中的行為及其對熔體粘度的影響規(guī)律。720℃時的測量數(shù)據(jù)表明，以Al-5Ti-1B和Al-3Ti-0．15C形式加入微量TiB2或TiC的鋁熔體，其粘度增加30％左右；分析了熔體粘度突變的原因，并提出了鈦化物／鋁熔體界面過渡區(qū)的假設(shè)。上述熔體經(jīng)一段時間的保溫后，出現(xiàn)了隨熔體溫度降低而粘度降低的異常變化，從鈦化物／鋁熔體界面過渡區(qū)的形成和整體的沉淀得到了合理的解釋。固態(tài)條件下鈦化物粒子周圍存在Ti濃度的梯度分布也間接證實(shí)了熔體條件下鈦化物／鋁熔體界面過渡區(qū)的存在。

Abstract:研究了組織形態(tài)對TC4鈦合金應(yīng)力松弛行為的影響。結(jié)果表明：200℃時等軸組織的抗應(yīng)力松弛性能好于魏氏組織；400℃和600℃時魏氏組織的抗應(yīng)力松弛性能稍高于等軸組織。不同組織的塑性應(yīng)變速率-應(yīng)力曲線具有相似的形狀。等軸組織晶粒發(fā)生輕微的長大，魏氏組織在發(fā)生粗化的同時，條狀物長徑比減小，有球化的傾向。

Abstract:The crystallization behavior of Zr Al Ni Cu bulk amorphous alloy during continuous heating is investigated. The results show that with increasing of heating rates, all the specific temperatures (Tg, Tx, and Tp) shift to the high temperature region, and the crystallization enthalpy and the enlarged supercooled liquid region increase, while the crystallized volume fraction corresponding to the peak temperature Tp decreases. Using Kissinger and Doyle plots, the activation crystallization energy can be evaluated. During continuous heating, the activation energy increases with increasing of the crystallized volume fraction at the early stage of crystallization, then decreases slightly and finally drops sharply. The value of activation energy obtained from Kissinger plots is a bit larger than that obtained from Doyle plots due to the change of the crystallized volume fraction at the specific temperature for different heating rates.

Abstract:研究了Y2O2S：Tb納米晶的發(fā)光性質(zhì)和能量傳遞過程，根據(jù)濃度猝滅曲線分析了納米Y2O2S中引起^5D3和^5D4能級濃度猝滅的相互作用類型分別為電偶極-電偶極和交換相互作用。納米Y2O2S中Tb離子^5D3-^7F3躍遷的發(fā)光壽命與相同摻雜濃度的體材料相比明顯縮短，根據(jù)引起濃度猝滅的相互作用類型對發(fā)光衰減曲線進(jìn)行擬合，得到理論和試驗(yàn)一致的結(jié)果。

Abstract:The influence of cementum extracts on the initial attachment of osteoblast has been measured by using the rat of cell attachment. The attachment index after 1,3, and 6 d, and the orientation index after 3 and 6 d have been obtained by the image analysis. It is observed that the extracts of cementum enhance the attachment and migration of osteoblast on the polished titanium surface. It is proposed that the cementum extracts can be used as the implantal coating materials in order to achieve an ideal osteointegration.

Abstract:通過軋制復(fù)合方法，在不同溫度條件下制備了Ag／Cu雙金屬板，研究了剝離載荷作用下分離強(qiáng)度與復(fù)合溫度的關(guān)系，測定了復(fù)合基體的硬度并觀察了分離界面形貌。結(jié)果表明：350℃復(fù)合的試樣因具有較大面積的異種金屬冶金結(jié)合區(qū)域而導(dǎo)致其分離強(qiáng)度較高；低于350℃復(fù)合試樣的冶金結(jié)合區(qū)域減少，高于350℃復(fù)合試樣的金屬表面趨向于被連續(xù)分布的氧化物隔離，這兩種情況均會使分離強(qiáng)度下降。

Abstract:The effects of mullite coating by sol-gel method and the particle sizes of SiC on the oxidation behavior of the recrystallized SiC were studied. The results showed that the oxidation resistance could be increased by the mullite coating formed on the surface of recrystallized silicon carbide at high temperature and with the increase of the thickness of mullite coating, having well effects both by mullite coating and coarse particles of the recrystallized SiC.

Abstract:主要研究了形變和相變交互作用對等溫鍛件顯微組織和力學(xué)性能的影響規(guī)律。結(jié)果發(fā)現(xiàn)形變和相變交互作用對Ti-17合金等溫鍛件的顯微組織、力學(xué)性能有重大影響，經(jīng)1次在β相區(qū)等溫形變與相變交互作用，鍛件高倍組織中的α相呈魚骨狀，在兩相區(qū)等溫鍛造后，得到有較厚α片層的網(wǎng)籃狀組織，各項(xiàng)力學(xué)性能指標(biāo)均較差；經(jīng)β相區(qū)和α β兩相區(qū)2次以上形變和相變交互作用并在β相區(qū)等溫鍛造后，得到的網(wǎng)籃組織中的條狀α細(xì)小均勻，交互作用次數(shù)愈多，α條愈細(xì)小、扭曲；如果交互作用次數(shù)少，在兩相區(qū)等溫鍛造后只能得到具有較厚α片層的網(wǎng)籃組織，交互作用次數(shù)多，則得到的是細(xì)小均勻的球狀α組織，但各項(xiàng)力學(xué)性能指標(biāo)均滿足要求。

Abstract:采用Ag粉和Ti粉作為焊料，對再結(jié)晶SiC陶瓷進(jìn)行熱壓反應(yīng)連接。研究了2種工藝，其中工藝1與傳統(tǒng)的擴(kuò)散焊工藝相似，即分別在不同的焊接溫度下保溫一定的時間；而工藝2則是首先在某一較高溫度下進(jìn)行短時間的保溫，以利于Ti與SiC母材發(fā)生適度的界面反應(yīng)，促進(jìn)界面結(jié)合，同時液相銀的出現(xiàn)將顯著緩解焊接應(yīng)力，隨后在另一相對較低的溫度下保溫較長時間，以利于Ag—Ti金屬間化合物的形成，有利于提高接頭的焊接強(qiáng)度和工作溫度。結(jié)果表明，采用工藝2獲得的接頭抗彎強(qiáng)度較高，達(dá)到SiC陶瓷母材強(qiáng)度的73．4％。微觀結(jié)構(gòu)研究表明，在界面處生成了反應(yīng)層，焊料產(chǎn)物主要由兩種相相間組成。EDX分析結(jié)果表明，界面處發(fā)生了元素的互擴(kuò)散。

Abstract:采用溶膠-凝膠法制備了微量 Yb2O3摻雜納米 TiO2顆粒,采用 XRD, TG-DTA, TEM等手段對試樣經(jīng)不同溫度熱處理后的結(jié)構(gòu)相變、表面形貌、顆粒大小等特性進(jìn)行了表征.實(shí)驗(yàn)表明溫度不高于 400℃時,試樣的顆粒粒徑較小,粒徑在 15 nm以下,比表面積大于 107.22 m2@ g-1, TiO2呈銳鈦型;在 400℃以上, TiO2粒徑迅速增大,微粒出現(xiàn)銳鈦相與金紅石相混晶結(jié)構(gòu);800℃時 TiO2微粒完全轉(zhuǎn)化成金紅石相.

Abstract:為系統(tǒng)地闡述送粉激光熔覆過程中激光能量的分配關(guān)系，在分析熔覆材料和基體材料與激光相互作用的基礎(chǔ)上，提出了激光能量有效利用率的概念，給出了檢測方法，并系統(tǒng)分析了影響因素。結(jié)果表明：在相同的送粉速率下，隨掃描速度的增加，熔覆材料吸收的能量增加，基體材料吸收的能量減少，激光能量有效利用率增大；在相同的掃描速度下，隨送粉速率的增加，熔覆材料吸收的能量增加，基體材料吸收的能量減少，激光能量有效利用率增大。對激光能量有效利用率隨掃描速度變化出現(xiàn)最大值的現(xiàn)象給出了合理的解釋。為定量描述激光熔覆工藝與工藝結(jié)果之間的關(guān)系奠定了基礎(chǔ)。

Abstract:Ta/W/Sn multilayer coatings were made on LY12 aluminium substrate by plasma spray. Effect of various parameters on the melting degree and deposition efficiency of feedstock has been investigated.The surface and the interfaces morphology of the multilayer coatings were observed using scanning electron microscopy. The weight gain of the coatings was weighed using precision mechanical balance.The tensile strength of the multilayer was determinated by mechnical testing machine. The chemical composition of these coatings was seperately obtained using auger energy spectrum and chemical analysis.The result shows that Ta/W/Sn multilayer coatings with fine structure and uniform thickness could be prepared by plasma spray processes.The degree of the powders melting is much affected by spray power and spray rate,and does not vary much with spray distance within the specific range.

Abstract:The effect of Ti/C (molar ratio) and Al content on phase constitution of combustion synthesized products by using Ti,Al,C and TiC powders as raw materials in the Ti Al C system has been studied. The experiment results show that the phase formation of combustion synthesized Ti3AlC2 powders are affected greatly by molar ratio of titanium to carbon and Al content in the raw materials. TiC is the main phase in the final product as the molar ratio of titanium to carbon is equal to 1 or 1.5, with little relationship to the amount of aluminum content. The Ti3AlC2 and Ti2AlC are the main phases in the final product as the molar ratio of titanium to carbon are equal to 2 and 3, respectively. Moreover, amounts of Ti3AlC2 and Ti2AlC increase in direct ratio with Al content, and later decrease with continuously increasing amount of Al. TiC is a medium product during the combustion process for the purpose of obtaining Ti3AlC2 powders.

Abstract:在(α+β)兩相區(qū)對Ti-1023合金進(jìn)行等溫壓縮試驗(yàn),實(shí)測高溫流動應(yīng)力曲線,討論流動應(yīng)力及顯微組織隨溫度及應(yīng)變速率的變化規(guī)律,實(shí)驗(yàn)結(jié)果表明,Ti-1023合金的流動應(yīng)力對應(yīng)變速率非常敏感;變形溫度對流動應(yīng)力的影響程度與應(yīng)變速率大小有關(guān),在ε=1.0s-1的較快速變形時,當(dāng)溫度由760℃提高到800℃時,流動應(yīng)力值下降約40MPa,而在ε=1.6×10-4s-1的慢速變形時,流動應(yīng)力值僅下降10MPa;顯微組織觀察結(jié)果表明,在相同溫度下較快速變形時(ε=1.0s-1),所得顯微組織比較細(xì)小、均勻,而慢速變形時(ε=1.6×10-4s-1),初生α相及組織比較粗大,亞β晶界也比較明顯。因此,在保證鍛件良好成形的前提下,Ti-1023合金在等溫鍛造時可采用適當(dāng)大的應(yīng)變速率。

Abstract:A rapidly solidified TiC/FeAl composite coating was fabricated on substrate of 1Cr18Ni9Ti stainless steel by laser cladding. The microstructure of composite coating, the growth morphology and growth mechanism of primary TiC carbide were investigated. Results show that the laser clad coating has a microstructure consisting of primary TiC,primary dendritic FeAl and small amount of interdendritic FeAl/TiC eutectic. The primary TiC carbide has an unique growth morphology of radial branching faceted dendritic colony, and its growth mechanism is still lateral growth.

Abstract:Worm powder extrusion molding(PEM) technology of hardmetal powder using novel binder system has been probed into. A newly developed binder system comprises a major fraction of low molecular weight components(LMWC) and a minor fraction of polymer.The binder was fabricated by heating melting method combined with solvent solving. The feedstock was mixed as a thick slurry at room temperature and was rapidly homogenised by stirring at a adequate shear force. The microstructure of the moulded specimes was observed by scanning electronics microscopy(SEM). The binder was debinded step by step. At the first stage of debinding, the LMWC were removed, and the interconnected capillaries were formed in the moluded green bodies. At the second stage of debinding, the remaining high molecular weight components were completely removed out. The second stage debinding heating rate can be faster than the first stage. The thermal debinding mechanism was studied by thermogravimetry (TG) and differential thermogravimetry(DTG). This research shows that the thermal debinding rate is controlled by three dimensional diffusion mechanism. The PEM hardmetal products with good properties and diameters of up to 20mm have been manufactured.