20钢复合渗铬中的相变

应用金相、X射线衍射和微区成分分析研究了20钢经离子氮化后在不同温度渗铬(复合渗铬)所得渗铬层的显微组织及其生成机制．不同温度复合渗铬层的表面层均由CrN(fcc)，β-Cr2N(hcp)和α-(Cr，Fe)(bcc)组成，其中α-(Cr，Fe)的含量随渗铬温度提高而减少．在复合渗铬过程中，原先的氮化白亮层发生扩散反应相变，生成复合渗铬白亮层，而扩散层中的相变主要是析出／共析转变，生成γ′氮化物析出带和／或一种类似珠光体的(α γ′)共析反应带。     

合金成分对Pr2Fel4B／α—Fe纳米复合永磁材料组织与磁性的影响

用XRD、TEM、Mossbauer谱和VSM等实验方法，研究了不同Pr含量、B含量和Cu含量的Pr2Fe14B／α—Fe型纳米复合快淬带的显微结构与磁性。结果表明：PrxFe94-x，B6合金在x＝8(α—Fe体积分数约30％)时磁性能最佳，Br＝1．29T，Hci＝461．7kA／m，(BH)man＝165．6kJ／m^3；Pr6．5(Fe8．5Co0．2)86．5—xCuxB5合金在x＝0．5时获得最佳的磁性能；随B含量增加，富B相在晶界分布，Pr8Fe92-xBx交换耦合减弱，磁性能单调下降。     

TiAlCNO过渡层组织结构及其对Al_2O_3涂层结构性能的影响

MT-TiCN/α-Al2O3多层涂层是高性能硬质合金CVD涂层刀具的典型涂层结构,得到广泛的应用和研究。TiAlCNO过渡层可以改善MT-TiCN/α-Al2O3涂层之间的结合性能。通过改变沉积气氛氧化势,制备了不同成分的TiAlCNO过渡层和MT-TiCN/TiAlCNO/Al2O3多层涂层,研究了沉积气氛氧化势对TiAlCNO过渡层和MT-TiCN/TiAlCNO/Al2O3多层涂层的结构性能的影响。结果表明:当沉积气氛中有CO2时,沉积TiAlCNO过渡层中可以检测到α-Al2O3相;随沉积气氛中CO2的增加,TiAlCNO过渡层中的Al含量增加,沉积在TiAlCNO过渡层表面的α-Al2O3涂层织构降低,结合强度增加。当TiAlCNO过渡层沉积气氛中CO2流量由0 L/min增加到1 L/min时,Al2O3涂层的织构系数TC(113)由0.64增加到1.33,而TC(012)由2.07降到1.5,TC(110)由1.99降到0.97;划痕临界载荷LC由36.5 N增加到51.7 N。     

稀土对ZAlSi12Cu2Mg1陶瓷层性能的影响

通过在Na2SiO2电解液体系中同时添加0．2g／L的Ce^3＋和不同含量的La^3＋以调整电解液组成，研究了Na2SiO3电解液中添加稀土离子对ZAlSi12Cu2Mg1合金微弧氧化陶瓷层相结构和力学性能的影响。结果表明，电解液中添加Ce^3＋和La^3＋，可以显著提高陶瓷层质量，其中添加0．2g／L的Ce^3＋和0．3g／L的La^3＋，所得陶瓷层主要由α—Al2O3、γ-Al2O3、Al2SiO3和非晶相组成，陶瓷层厚为157μm，硬度（HV）为947，经6000r磨损后，ZAlSi12Cu2Mg1合金基体的磨损量为102．2mg，而陶瓷层S1磨损量为19．7mg，仅为铝合金基体的19％。     

电弧离子镀沉积Al(Cr)-O-N扩散阻挡层的研究

采用电弧离子镀方法在高温合金DSM11基材上沉积Al-O-N和Cr-O-N薄膜，研究了不同O2，N2流量对薄膜相结构的影响以及高温下DSM11／NiCoCrAlY，DSM11／Al-O-N／NiCoCrAlY和DSM11／Cr-O-N／NiCoCrAlY体系的元素互扩散行为。实验结果表明，Al(Cr)-O-N薄膜均为多晶膜，分别具有α-Al2O3 六方AlN和Cr2O3 CrN的相结构，随着N2，O2流量的改变，两相的相对含量发生变化。在1050℃下氧化100h后，Al-O-N层阻挡基体与涂层间元素互扩散的作用优于Cr-O-N层。扩散阻挡层对涂层的氧化动力学影响不大。     

不同层厚比的铜/铝层状复合板剪切特性研究

为研究铜/铝复合板的剪切特性,对三种不同层厚比的铜/铝复合板进行斜刃横剪加工实验,分析了不同层厚比下铜/铝复合板的断面形貌特征、加工硬化及剪切力的变化规律。结果表明:不同层厚比的复合板材剪切断面形貌特征略有不同,在铜层占比较大时,铜层也会出现断裂带。随着铜层占比的增大(即铜/铝层厚比增加),剪切断面平整性变好,塌角、毛刺逐渐增大,剪切带逐渐增大,断裂带逐渐减小,加工硬化程度及范围增加,剪切力增大。在层厚比较小(1∶9和2∶8)时,复合板材断裂为剪切断裂和微孔聚集型断裂的混合型断裂模式,而层厚比较大(3∶7)时为剪切断裂模式。     

不锈钢／铝合金／不锈钢多层复合板的成形性能

通过拉伸实验测试了不锈钢／铝合金／不锈钢三层、五层复合板的成形性能影响参数：厚度异性系数r、应变强化指数n和屈强比σ0．2／σb，结果表明轧制复合变形量、扩散退火温度对不锈钢／铝合金／不锈钢多层复合材料的成形性能参数有较明显的影响。     

（1-x）La2／3Ca1／3MnO3／xCr2O3复合材料的电输运性质和磁电阻效应

用固相反应法制备了（1-x）La2／3Ca1／3MnO3/xcr2O3（x为摩尔分数）复合样品，实验研究了在外加0～3T的磁场下，Cr203含量对该复合样品的电输运性质及磁电阻的影响。结果发现随着Cr2O3含量的增加，金属．绝缘体（M-I）转变温度耳急剧降低，并且当Cr2O3，含量x〉0．1时此转变消失。与此同时，电阻率随其含量增加而快速增大，特别的是在样品中观察到了较宽温度范围内显著增强了的磁电阻。这种结果的出现可能与Cr2O3有关的新相偏析在La2／3Ca1／3MnO3（LCMO）晶界和颗粒界面有关。     

电解液中Ce(NO_3)_3含量对ZAlSi12合金微弧氧化层特性的影响

研究Na2SiO3-NaOH体系电解液中Ce(NO3)3含量在0～0.20g/L范围内变化时对ZAlSi12合金表面微弧氧化陶瓷层组织和厚度的影响。采用SEM、XRD分析微弧氧化处理后陶瓷层的表面形貌和相组成。结果表明:随着Ce(NO3)3含量增加,陶瓷氧化层厚度逐渐增大,电解液中Ce(NO3)3加入量0.15g/L时可获得最大厚度为170μm的陶瓷层;电解液中加入Ce(NO3)3后,膜层仍主要由α-Al2O3和γ-Al2O3相组成,但α-Al2O3相的相对含量增加。     

电解液中(NaPO3)6对ZAlSi12Cu2Mg1微弧氧化陶瓷膜的影响

通过在硅酸盐电解液体系中加入（NaPO3）6，研究其对ZAlSi12Cu2Mg1表面微弧氧化陶瓷膜层厚度、孔隙率及相组成的影响。结果表明，当（NaPO3）6的加入量在0～12g／L内逐渐增加时，微弧氧化陶瓷膜层的厚度逐渐上升。加入量为0～6g／L逐渐增加时，膜层孔隙率逐渐下降，超过6g／L时，孔隙率开始上升。电解液中未加（NaPO3）6时，陶瓷膜层主要由γ-Al2O3、α-Al2O3及Al2SiO5组成，α-Al2O3和γ-Al2O3相衍射峰强度大致相同；而加入6g／L（NaPO3）6后，陶瓷层中没有发现Na^＋或PO3^-，但α-Al2O3相的衍射峰强度明显高于γ-Al2O3相，且铝基体的衍射峰强度有所降低。     

Structural, mechanical and corrosion properties of TiOxNy/ZrOxNy multilayer coatings

Results on the deposition and characterization of TiO_xN_y/ZrO_xN_y multilayers, with bilayer periods of 20 and 400 nm, are presented. The coatings were deposited on TiNiNb alloy substrates by the pulsed magnetron sputtering method. The elemental composition, hardness, adhesion and corrosion resistance of the coatings were analyzed.As resulted from the XPS analysis, the individual layers consisted of a mixture of titanium or zirconium oxynitrides and corresponding oxides. X-ray analysis revealed that the coatings were amorphous. Only slight differences between the microhardness and adhesion values of the coatings with small and large bilayer period Λ were found. The experiments also showed that the multilayered coatings improved the corrosion resistance of the uncoated alloy and reduced the amount of ion release in artificial body fluids.     

MOCVD growth and characterizations of BxAl1−xAs and BxAl1−x−yInyAs alloys

Zinc-blende B_xAl_1−xAs and B_xAl_1−x−yIn_yAs alloys have been grown on exactly oriented (0 0 1)GaAs substrates by low pressure metalorganic chemical vapor deposition (LP-MOCVD). The influence of susceptor coating, growth temperature and gas-phase boron mole fraction on boron incorporation into AlAs has been comprehensively investigated. It has been found that boron incorporation into AlAs could be enhanced and the optimal growth temperature range of B_xAl_1−xAs alloys changed from 580 °C to 610 °C when SiC-coated graphite susceptors were replaced by the non-coated ones. In this study, the maximum boron composition x of 2.8% was achieved for the pseudomorphically strained B_xAl_1−xAs alloys. AFM measurements show that RMS roughness of B_xAl_1−xAs alloys increased sharply with the increase of gas-phase boron mole fraction. Raman spectra of B_xAl_1−xAs alloys show a linear increase of the BAs shift with boron composition x. Based on BAlAs deposition, bulk B_xAl_1−x−yIn_yAs (x = 1.9%) quaternary alloy was grown lattice-matched to GaAs successfully. Moreover, 10-period BAlAs/GaAs and BAlInAs/GaAs MQW heterostructures were also demonstrated.     

High strength and good ductility of casting Al-Cu alloy modified by PrxOy and LaxOy

A modified Al-Cu alloy with high tensile strength and ductility of about 574.0 MPa and 10.4%, respectively, was obtained by adding multiple rare earth oxides (Pr_xO_y and La_xO_y) as modifier. Compared with the unmodified Al-Cu alloy, the tensile strength and ductility of the modified sample were increased by 24.3% and 42.5%, respectively. The improvement both in the strength and ductility may attribute to the finer crystal grains and dendrites, more homogeneously distributed θ′ phase precipitates and the intermetallic compounds formed at the crystal grain boundaries as well as in the space of the dendrites.     

Hydrothermal synthesis of superconductors Ba1−xKxBiO3 and double perovskites Ba1−xKxBi1−yNayO3

Superconductors Ba_1−xK_xBiO₃ and body-centered double perovskites Ba_1−xK_xBi_1−yNa_yO₃ have been selectively synthesized by a facile hydrothermal route. The appropriate ratio and adding sequence of initial reagents, alkalinity, reaction temperature and time are the critical factors that influence the crystal growth of the compounds. The purity and homogeneity of the crystals were detected by the ICP, SEM, EDX and TEM studies. Magnetic measurements show that the superconducting transition temperatures T_C of Ba_1−xK_xBiO₃ decrease from 22 K (for x = 0.35) to 8 K (for x = 0.55) with increasing the K doping level.     

铸造CAD／CAE／ES／PDM／ERP一体化及集成技术研究

详细阐述了支持铸造工艺设计、工艺优化、工艺信息管理、企业管理的系统研究与应用特点,在此基础上提出了基于PDM平台的铸造CAD／CAE／ES／PDM／ERP一体化框架体系,在华铸实验室现有软件体系（华铸CAE／CAD／PDM／ERP）及应用的基础上,设计与实现了一体化系统关键点及其集成技术。最后,以若干实际案例来证明本研究一体化系统的实用性。     

生物医用NiTi形状记忆合金腐蚀研究进展

镍钛形状记忆合金(NiTi-SMA)具有较好的耐腐蚀和机械性能,在口腔和临床医学中有着大量而广泛的应用。NiTi-SMA腐蚀后释放Ni²⁺会引发细胞毒性和过敏反应,进一步提高NiTi-SMA的耐蚀性是目前生物医学材料领域发展的核心之一。本文对近年来国内外有关口腔医学和临床医学中常用NiTi-SMA的腐蚀研究现状进行了总结,同时也对NiTi-SMA增材制造及表面改性技术进行了评述,以期为开发高性能抗腐蚀生物医用NiTi-SMA提供一定的指导意义。     

Li掺杂Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li(1/7-x))O3高熵陶瓷的制备及介电性能研究

近年来,在高熵合金基础上发展起来的高熵陶瓷逐渐引起了研究者的广泛关注,其出现为开发高性能的无机非金属材料提供了新的设计思路。本文采用固相法制备了BaMO3基钙钛矿型高熵陶瓷Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li(1/7-x))O3 (x = 0, 2.3%, 5.3%, 8.3%, 11.3%),并研究了Li含量对高熵陶瓷物相结构、微观形貌及介电性能的影响。结果表明,Li含量对陶瓷结构的影响不大,陶瓷均保持立方钙钛矿结构,且无杂相产生;陶瓷的晶粒尺寸相对较均匀。当x = 0时,即B位七元等摩尔比Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li1/7)O3高熵陶瓷,其介电常数达到了最大值2920 (@100 Hz),相较于已报道的不掺Li的六元高熵钙钛矿陶瓷Ba(Ti1/6Sn1/6Zr1/6Hf1/6Nb1/6Ga1/6)O3提升了近50倍。     

CAD／CAE／CAM／PDM应用分析

分析了CAD／CAE／CAMP／PDM的作用和关系,介绍了常用CAD／CAE／CAMPDM软件及选型方法,为企业建立和应用CAD／CAE／CAM／PDM提供了依据。     

Thermoelectric properties of Sn1−x−yTiySbxO2 ceramics

Thermoelectric properties of Sn_1−x−yTi_y Sb_xO₂ ceramics were investigated in detail. The addition of Sb into SnO₂ matrix increased the electric conductivity, σ. The increase in the σ value should be caused by the increase in the carrier concentration. The Seebeck coefficients of all the samples were negative, which means that these samples have n-type conduction. The samples of this study have porous structure. The maximum Z value of all the samples measured in this study was 2.4 × 10⁻⁵ K⁻¹.     

Ti/Mn(0.8-x)SnxIr0.2O2电极的电容性能研究

采用热分解法制备了Ti/Mn_(0.8-x)SnxIr_0.2O_2三元氧化物电极材料。通过扫描电子显微镜,X射线衍射、循环伏安和交流阻抗谱等分析了Ti/Mn_(0.8-x)Sn_xIr_0.2O_2电极材料的组织结构和电容性能。结果表明:随SnO_2含量增加,氧化物涂层中正方结构Mn_3O_4相逐渐减少,正方结构SnO_2相逐渐增加。与锰铱二元氧化物相比,SnO_2的加入可明显改善电极材料在0~0.5 V区间的电流响应,并促进氧化锰活性的发挥,但在一定程度上也抑制了氧化铱的活性。SnO_2的加入也改变了电极材料的电荷转移电阻、弛豫时间常数、以及不同频率下的电容响应速度。相比其它电极材料,Ti/Ir_0.2Mn_0.6Sn_0.2O_2电极材料在低频范围(≤1 Hz)有更好的电容响应和更高的活性,因而获得最高的比电容值。