高能球磨制备TiB_2/TiC纳米复合粉体

研究了通过高能球磨制备ＴｉＢ２／ＴｉＣ纳米复合粉体的反应过程和机理,对粉体的显微结构进行了表征．实验结果表明,采用金属 Ｔｉ和 Ｂ４Ｃ为原料,在球磨过程中, ＴｉＣ先于 ＴｉＢ２形成．球磨５ｈ后Ｔｉ与Ｂ４Ｃ反应生成ＴｉＢ２和ＴｉＣ,在随后的长时间高能球磨过程中ＴｉＢ２和ＴｉＣ两相保持稳定．球磨 ３０ｈ后,直径约 ８ｎｍ的 ＴｉＣ纳米粒子分布在 １００～２００ ｎｍ的 ＴｉＢ２粒子中,形成均匀分布的纳米ＴｉＢ２／ＴｉＣ复合粉体．     

Early Osteogenic Marker Expression in hMSCs Cultured onto Acid Etching-Derived Micro- and Nanotopography 3D-Printed Titanium Surfaces

Polyetheretherketone (PEEK) titanium composite (PTC) is a novel interbody fusion device that combines a PEEK core with titanium alloy (Ti6Al4V) endplates. The present study aimed to investigate the in vitro biological reactivity of human bone-marrow-derived mesenchymal stem cells (hBM-MSCs) to micro- and nanotopographies produced by an acid-etching process on the surface of 3D-printed PTC endplates. Optical profilometer and scanning electron microscopy were used to assess the surface roughness and identify the nano-features of etched or unetched PTC endplates, respectively. The viability, morphology and the expression of specific osteogenic markers were examined after 7 days of culture in the seeded cells. Haralick texture analysis was carried out on the unseeded endplates to correlate surface texture features to the biological data. The acid-etching process modified the surface roughness of the 3D-printed PTC endplates, creating micro- and nano-scale structures that significantly contributed to sustaining the viability of hBM-MSCs and triggering the expression of early osteogenic markers, such as alkaline phosphatase activity and bone-ECM protein production. Finally, the topography of 3D-printed PTC endplates influenced Haralick’s features, which in turn correlated with the expression of two osteogenic markers, osteopontin and osteocalcin. Overall, these data demonstrate that the acid-etching process of PTC endplates created a favourable environment for osteogenic differentiation of hBM-MSCs and may potentially have clinical benefit.     

热暴露对SiC纤维增强Ti基复合材料基体织构的影响

本文利用电子背散射衍射（EBSD）技术,研究了高温热暴露对SiC纤维增强Ti-6A1—4V复合材料基体织构的影响。结果表明,相对于制备态复合材料较为集中的晶粒取向,900℃10h热暴露后的复合材料其晶粒生长的方向既有基面方向,又有棱面方向,同时还存在锥面方向。随着热暴露时间的延长,900℃75h热暴露的复合材料基面方向的生长方式与900℃10h热暴露的复合材料情况恰好相反。另外,无论是基面方向还是棱面方向,随着热暴露时间的延长,晶粒生长的取向均有向单一取向演化的趋势,且锥面方向上的生长会逐渐消失。     

钛酸钡添加量对埋容用环氧-钛酸钡-玻璃布板材性能的影响

采用热固化层压方法制备了环氧-钛酸钡-玻璃布(EBG)板材,并分析钛酸钡(BTO)添加量对埋容用EBG板材各项性能的影响。结果表明:随着BTO填料添加量的增大,EBG板材的实际密度先接近后偏离理论密度,孔隙率先减小后增大,耐浸焊时间、剥离强度先增大后减小,5%热分解温度和介电常数增大;当BTO的质量分数为80%左右时,埋容用EBG板材具有较好的综合性能;EBG板材为一种混联模型。     

预钙化加速类骨磷灰石在镍钛合金表面生长的电化学阻抗谱

通过酸碱处理活化NiTi合金表面,在模拟体液中仿生生长类骨磷灰石层以改善其生物相容性.采用电化学阻抗谱研究了预钙化对加速磷灰石沉积的影响,并基于双层模型建立了电子等效电路.结果表明:随着在模拟体液中浸泡时间的延长,化学处理的NiTi合金表面类骨磷灰石不断生长,并且添加预钙化试样浸泡3 d,即可在合金表面生长出均匀完整的类骨磷灰石层,而未预钙化试样表面沉积物稀少.对应电子等效电路中,预钙化试样电阻值明显大于未预钙化试样的,显示预钙化促进了活化NiTi合金表面类骨磷灰石的生长.     

High Temperature Oxidation of FGH96 P/M Superalloy

High temperature oxidation behaviors of FGH96 P/M superalloy have been studied in air at temperatures ranging from 600 to 1000℃. By means of isothermal oxidation testing,X-ray diffraction,SEM(scanning electron microscopy),and EDS(energy dispersive X-ray spectroscopy) analyses,the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased,the oxidation rate,the scale thickness,and scale spallation increased. FGH96 P/M superalloy exhibits good oxidation resistance at temperature below 800℃. The oxidation kinetics follows an approximately parabolic rate law,and the oxide layer was mainly composed of Cr2O3,TiO2,and a little amount of NiCr2O4. The oxidation is controlled by the transmission of chromium,titanium,and oxygen through the oxide scale.     

钛合金焊接件密封问题研究

水下大功率振源体的质量关键除了焊接质量就是密封面的密封性,特别是焊接结构的强振体能否达到良好的密封性是工艺结构的一大难点。根据我们现有的机械加工设备能力和振源体结构特点,无法对振源体组焊件整体真空消应热处理后进行密封面的加工。文中介绍了采用修配座圈窗盖和增大O形圈截面直径的方法,提高了振源体组件的密封性。     

华能玉环电厂1000MW超超临界2号机组凝汽器组合安装施工技术方案

凝汽器是发电厂重要设备之一,凝汽器的安装速度和质量直接影响着整个工程施工进度网络节点的顺利实现和今后整机的运行水平。华能玉环电厂2号机凝汽器安装施工过程中,克服了多种不利因素,制定科学便捷的施工工序和施工方案,以最短的时间完成了凝汽器的整体安装任务,为后续的酸洗和吹管,以至整套启动赢得了宝贵的时间。     

增材制造TC4钛合金在激光抛光前后的电化学腐蚀性能

对表面已进行喷砂处理的增材制造TC4钛合金在氩气环境下进行激光抛光实验,通过极化曲线测试研究了抛光前、后钛合金的耐蚀性,并结合表面粗糙度、晶粒尺寸、表面残余应力以及显微组织分析了激光抛光对TC4钛合金耐蚀性的影响。研究结果表明:抛光钛合金的自腐蚀电位与自腐蚀电流密度均大于未抛光钛合金,说明抛光钛合金相比于原始钛合金的被腐蚀倾向更小,但其一旦受到腐蚀,腐蚀速率会略大于原始钛合金。自腐蚀电位的升高源于钛合金表面粗糙度的降低,自腐蚀电流密度的增大则是因为表面晶粒的细化以及残余拉应力的存在。     

In Situ Synthesis of Titanium Nickel Intermetallic Compounds Layer and TiN Coating By Laser Cladding

1 Introduction Laser cladding technology has been widely used in ma- terial processing and tool repairing because it causes little distortion and leads to high quality coatings [1]. Since the appearance ofhigh power diode lasers, the laser cladding is more efficient, economical and flexible[2￣5]. Titanium nickel alloys have excellent properties such as low density, high strength, and high chemical stability, which have promoted their applications in the aerospace, chemical, petrochemical and …