等离子喷涂钼基非晶-纳米晶复合涂层的组织与性能

一种多元素钼基非晶-纳米晶合金粉末(含C、Si、B、Cr、Fe、Ni、Mo等)作为喷涂材料,用大气等离子喷涂在316L不锈钢基体上制备涂层,用X射线衍射仪、扫描电镜、透射电镜、显微硬度仪分析测量涂层的组织和性能,并用谢乐公式计算晶粒尺寸。结果表明：所制备的涂层均匀致密,涂层含有非晶和纳米晶,颗粒尺寸为10～50nm;这种非晶纳米晶复合涂层的硬度和弹性模量分别高达1055HV和214．40GPa。     

激光熔覆AlCoCrFeNiSix高熵合金涂层的微观组织及耐蚀性能

利用激光熔覆技术在AISI 304不锈钢表面制备了AlCoCrFeNiSix（x=0.1，0.2，0.3，0.4，0.5）高熵合金涂层。采用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、能谱分析仪（EDS）、透射电子显微镜（TEM）、维氏硬度计和电化学工作站等，分析了Si元素对AlCoCrFeNiSix高熵合金涂层微观组织和性能的影响。结果表明：AlCoCrFeNiSix高熵合金涂层由体心立方（BCC）固溶体晶粒构成。随着Si元素含量的增加，Si元素置换固溶使晶格收缩，晶粒逐步细化，纳米尺度球状AlNi相在晶粒内脱溶，少量的Cr23C6碳化物沿晶界析出。微观组织的演化导致涂层的显微硬度升高，最大硬度达到848.1 HV0.3。AlCoCrFeNiSix高熵合金涂层的热力学腐蚀倾向和均匀腐蚀速率均低于基材AISI 304不锈钢。Si元素的掺杂提高了钝化膜的修复能力和稳定性，使腐蚀机制从自催化发展的点蚀转变为晶间腐蚀。     

熔覆电流对FeCoCrNiMn高熵合金涂层组织与性能的影响

目的 研究等离子熔覆电流对FeCoCrNiMn高熵合金涂层组织与性能的影响。方法 采用等离子堆焊工艺在65Mn钢基体上制备等摩尔比的FeCoCrNiMn高熵合金涂层。通过观察涂层的宏观表面特征来判断等离子熔覆技术制作高熵合金涂层的宏观效果。利用金相显微镜（OM）、扫描电镜（SEM）以及X射线衍射技术（XRD）观察涂层显微组织,并分析涂层的成分和相组成。采用维氏硬度显微测试计测量合金涂层的表面硬度和基体至涂层的层深硬度。结果 等离子熔覆技术制备的合金涂层无裂纹,涂层平均厚度达到2 mm。涂层元素与熔覆粉末元素比例一致,除去部分Fe元素由基体进入涂层之外,涂层依旧为单相FCC固溶体结构,组织形态为枝晶。涂层与基体结合处可以观察到明显的柱状晶区和热影响区（HAZ）。随着电流的增大,枝晶组织逐渐变粗,而FeCoCrNiMn高熵合金涂层的表面硬度逐渐减小,在190 A处,硬度发生突变达到最大值366.3HV,170 A处为最小值258.78HV。沿层深方向,涂层硬度变化不大,热影响区内由上到下,硬度先增大后减小。结论 等离子熔覆技术制备高熵合金涂层有明显的优势,且具有制作大面积表面涂层的潜力,涂层厚度可以达到毫米级。电流大小改变,FCC相组成没有发生改变,而组织结构发生改变,随着电流变大,枝晶组织变粗,涂层硬度逐渐下降。     

喷涂工艺对超音速火焰喷涂Al-Cu-Fe-Si准晶合金涂层性能的影响

目的使用活性燃烧高速燃气喷涂(AC-HVAF)方法制备高质量的Al-Cu-Fe-Si准晶涂层,研究喷涂工艺对涂层性能的影响。方法采用气雾化Al-Cu-Fe-Si准晶合金粉末,利用AK02T型AC-HVAF喷涂系统制备Al-Cu-Fe-Si准晶涂层材料。通过X射线衍射及扫描电镜观察分析准晶合金粉末和涂层的组织与结构,通过电化学工作站、显微硬度计和接触角测试仪等手段分析准晶合金涂层的耐蚀性、显微硬度及抗粘性能。结果对气雾化准晶Al-Cu-Fe-Si合金粉末的研究发现,冷却速率显著影响准晶合金粉末的组织,在冷却速率较快的粉末中形成胞状晶组织,准晶I相含量较高。对准晶合金涂层进行热处理,高温退火显著提高了涂层的硬度,950℃退火12 h后,硬度值达到(724±153)HV0.1。分别对准晶合金涂层和基体45~#钢的接触角进行测量,准晶合金涂层的接触角最大为95°,而45~#钢的仅为79°。通过电化学工作站测试比较涂层的耐蚀性,发现在3.5%(质量分数)的Na Cl溶液中,喷涂在45~#钢和5052铝合金基体上的涂层腐蚀电流密度J_(corr)分别为6.8×10~(-6),2.0×10~(-7)A/cm~2。结论不同粒径的气雾化准晶合金粉末的相组成不同,选择合适的粒径是保证铝基准晶合金涂层质量的前提。对涂层进行合适的热处理可以有效地提高涂层的显微硬度,铝基准晶合金涂层的接触角较45~#钢的高,提高了基体的抗粘性。不同基体上制备的准晶合金涂层的耐蚀性有很大差异,5052铝合金基体上的准晶涂层耐蚀性优于喷涂在45~#钢基体上的涂层。     

钼对高铬铸铁激光熔覆层组织和硬度的影响

在两种不同的扫描速度下（100mm/min、300mm/min）,在20钢基体表面激光熔覆钼粉与高铬铸铁复合粉末,利用扫描电子显微镜、维氏硬度计检测了不同钼粉含量时（0.5%、3%、5%、7.5%、10%）熔覆层的显微组织和硬度。结果表明,钼粉与高铬铸铁复合粉末经激光熔覆后,晶粒细化,组织致密,无裂纹、气孔等缺陷;在较低的扫描速度下,加入钼后,能细化晶粒,促进条状珠光体向胞状奥氏体枝晶转变,不同钼含量下熔覆层的平均硬度分别为160、172、193、212和226 HV0.2;在较高的扫描速度下,钼加入后,能抑制碳化物生长,促进长条状的初生合金碳化物向方块状、层片状的碳化物转变,有利于抑制开裂。不同钼含量下熔覆层的平均硬度分别为586、612、637、682和712 HV0.2。     

7A04表面纳米化组织的热稳定性

用旋转辊压塑性变形方法在7A04铝合金表层获得纳米晶组织，用DSC和透射电镜研究了表面纳米晶组织的热稳定性。DSC测试结果表明7A04铝合金表面纳米晶的再结晶温度在473K左右，透射电镜分析表明表面纳米化样品473K退火后晶粒没有明显长大，平均晶粒尺寸约100nm。旋转辊压变形160min，表面层显微硬度由160HV升高到335HV，473K退火后显微硬度下降至250HV，但仍高于基体，573K退火后从表层到基体的显微硬度均明显下降。结果表明7A04表面纳米化组织的使用温度在473K以下。     

激光熔覆CoCrCu0.4FeNi高熵合金涂层的微观组织和性能

目的 提高零部件的硬度和耐磨性。方法 采用Ni-Cr-B-Si、Co-Cr-B-Si自熔合金以及Cu粉在Q235钢基体上激光熔覆CoCrCuFeNi高熵合金涂层,激光功率为2.2、2.4 kW,扫描速度为9、12 mm/s,利用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分析涂层的微观组织,并测试了涂层的显微硬度。结果 Cu含量较高的涂层与基体形成了良好的冶金结合,但在涂层中存在严重的Cu偏析现象;Cu含量较低的涂层与基体结合处附近存在少量孔洞缺陷,局部区域具有调幅分解,涂层微观组织主要由树枝晶和枝晶间组成,树枝晶为FCC1,富Cu贫Cr,枝晶间为FCC2,富Cr贫Cu,还存在少量的纳米相,形成了具有C和B间隙固溶的CoCrCu_0.4FeNi高熵合金涂层。熔覆的涂层厚度为2.19～2.58 mm,涂层枝晶厚度为2.2～7.3μm,且枝晶越小,硬度越高。涂层的显微硬度为280～300HV0.2,基体的硬度为110～130HV0.2,约为基体的2.5倍。结论 采用Ni-Cr-B-Si、Co-Cr-B-Si自熔合金和Cu粉激光熔覆了CoCrCuFeNi高...     

7A04表面纳米化组织的热稳定性

用旋转辊压塑性变形方法在7A04铝合金表层获得纳米晶组织,用DSC和透射电镜研究了表面纳米晶组织的热稳定性.DSC测试结果表明7A04铝合金表面纳米晶的再结晶温度在473K左右,透射电镜分析表明表面纳米化样品473K退火后晶粒没有明显长大,平均晶粒尺寸约100nm.旋转辊压变形160min,表面层显微硬度由160HV升高到335HV,473K退火后显微硬度下降至250HV,但仍高于基体,573K退火后从表层到基体的显微硬度均明显下降.结果表明7A04表面纳米化组织的使用温度在473K以下.     

WC/FeAl金属间化合物基金属陶瓷涂层的冷喷涂制备

采用WC/Fe/Al混合粉末,通过机械合金化制备40v0l％ WC/Fe(Al)固溶体复合粉末,利用冷喷涂沉积涂层并结合热处理原位反应制备了WC/FeAl金属间化合物基金属陶瓷涂层.研究了球磨时间对复合粉末相结构、晶粒尺寸及组织结构的影响,并分析了冷喷涂WC/FeAl金属间化合物基金属陶瓷涂层的组织和显微硬度.结果表明,机械合金化可获得WC陶瓷颗粒呈微/纳米多尺度分布的WC/Fe(Al)金属陶瓷复合粉末,球磨36 h的复合粉末基体相平均晶粒尺寸约为90 nm,冷喷复合涂层组织致密、多尺度WC颗粒在基体中均匀弥散分布,涂层显微硬度约为1060 HV0.3,涂层在650℃热处理后发生Fe(Al)固溶体向FeAl金属间化合物的原位转变,制备出了WC/FeAl金属间化合物基金属陶瓷涂层.     

超音速火焰喷涂制备钼基非晶纳米晶涂层的研究

利用超音速火焰喷涂(HVOF)技术，在0Cr13Ni5Mo不锈钢基体上成功的制备出了一种Mo基非晶纳米晶复合涂层。这种涂层组织均匀致密，孔隙率小，约为3．4％，呈典型的层状分布；涂层是由非晶和纳米晶组成，在非晶基体中均匀分布了纳米晶粒。根据衍射峰的半高宽，计算出Mo基涂层中的晶粒平均尺寸为25～70nm，与通过透射电镜的观察得到晶粒大小数20～70nm相符；涂层具有较高的硬度，平均显微硬度为859．0HV50；所获得的非晶纳米晶涂层具有较高的热稳定性，在1020．1℃以下使用，不会发生晶型转变。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).