氟锆酸钾盐混合物对Mg-3Y-3.5Sm-2Zn合金组织和性能的影响

制备了三种氟锆酸钾(K2ZrF6)盐混合物(M),分别在三个温度下将三种盐混合物加入到铸态Mg-3Y-3.5Sm-2Zn合金中。通过差热分析(DSC),X射线衍射(XRD),光学显微镜(OM),扫描电子显微镜(SEM),能量色散谱(EDS)和拉伸试验研究了合金的显微组织和力学性能,讨论了K2ZrF6盐混合物在合金中的晶粒细化机理。结果表明,铸态Mg-3Y-3.5Sm-2Zn合金由α-Mg,Mg12(Y,Sm)Zn 和 (Mg,Zn)3(Y,Sm)三种相组成。SEM和XRD检测发现,添加K2ZrF6盐混合物不会在合金中产生新的相。在780°C下加入M3盐(60wt% K2ZrF6-20wt% NaCl-20wt% KCl)时,合金的晶粒细化效果最佳。通过在780℃下加入三种盐,铸态Mg-3Y-3.5Sm-2Zn合金的力学性能得到提高,由M3盐细化后的合金具有最佳的力学性能。K2ZrF6盐混合物可细化铸态Mg-3Y-3.5Sm-2Zn合金,这是由于Mg和K2ZrF6之间还原反应得到的细Zr质点和富锆区在合金中起到的晶粒细化作用。     

双时效对Ti-4Al-5Mo-6Cr-5V-1Nb合金显微组织和力学性能的影响

研究了固溶、固溶后单时效以及固溶后双时效处理对Ti-4Al-5Mo-6Cr-5V-1Nb合金组织和力学性能的影响。结果表明,820℃下固溶0.5 h后,合金中的α相完全溶解;单/双时效合金的硬度均随时效时间增加先升高后降低;合金经300℃/8 h+500℃/8 h双时效处理后可达到4580 MPa的峰值硬度(HV),1462 MPa抗拉强度以及3.4%延伸率,其强度比原始合金高6%,也高于单时效合金。界面能计算结果表明ω相使α相形核的阻力降低50%,促进了α相的析出并细化α板条,从而提升合金的硬度,强度及塑性。     

基于支持向量机和磁记忆技术的管道缺陷深度的定量化反演研究

金属管道表面往往存在不同深度的腐蚀缺陷。金属磁记忆检测技术是目前唯一能对铁磁性构件的早期损伤进行诊断的无损检测技术,然而磁记忆原始信号本身并不能直接实现对管道腐蚀缺陷深度特征的定量化识别,进而无法实现对管道腐蚀程度的预警。针对该问题,采用支持向量机方法建立了管道缺陷深度的定量化反演模型,利用该模型对管道上深度为1~15mm的腐蚀缺陷进行了多次反演,反演结果的平均误差为2.398mm,平均均方根误差为3.205mm,结果表明,模型对管道腐蚀缺陷深度的定量化反演是可行的。研究结果可为该领域的研究提供一定的参考,且具有较高的实际应用价值。     

高熵合金CrNbTiVZr的微观组织及其在模拟PEMFC环境中腐蚀行为研究

采用真空电弧熔炼和热处理制备了CrNbTiVZr高熵合金,利用XRD、SEM/EDS、动电位与恒电位极化曲线测试及XPS表面分析等方法,研究了高熵合金铸态及退火后的微观组织特征以及合金在模拟PEMFC环境中的电化学腐蚀行为及其钝化膜组成。结果表明,CrNbTiVZr高熵合金的铸态和退火组织均由富集Ti、Nb元素的无序BCC相和富集Cr、V、Zr元素的Laves相组成。铸态和退火合金在模拟PEMFC阴极环境中腐蚀电流密度Icorr均比304SS不锈钢下降一个数量级,具有较好的耐蚀性和稳定性,但在阳极环境中其耐蚀性与304SS相当,其中铸态合金的稳定性较差。合金在阴极环境良好的耐蚀性主要与其表面形成由Cr2O3、Nb2O5、V2O3、Ti2O3及ZrO2组成的致密钝化膜关系密切。     

Low Frequency Electromagnetic Casting of 2195 Aluminum-Lithium Alloy and Its Effects on Microstructure and Mechanical Properties

In this study,the low frequency electromagnetic casting(LFEC) technology was adopted to fabricate 2195 Al-Li alloy.The microstructure and solid solubility of as-cast 2195 alloys,as well as the second phase precipitation and tensile properties after aging,were investiagated and compared with the counterpart direct chill casting 2195 alloy.Our results indicate that LFEC can significantly improve the microstructure and metallurgical quality of as-cast alloy,and increase the number density of θ'(Al_2 Cu) and T_1(Al_2 CuLi) phases during aging treatment due to the enhanced solubilities of alloying elements.The tensile properties of 2195 aged alloy cast by LFEC were hence improved evidently.     

Co-Free High-Entropy Alloys Powders Immobilized by Electrospray and Microf luidics for Decolorization of Azo Dye

In recent years,high-entropy alloys(HEAs) have received more and more attention due to their unique microstructure and properties.Several researchers have reported that some ball-milled(BM) HEAs powders possess prominent decolorization performance for azo dyes.Three kinds of Co-free HEA powders(AlCrFeMn,AlCrFeNi and FeCrNiMn) have been synthesized by ball milling in this work,of which AlCrFeMn shows the best decolorization efficiency for DB6 aqueous solution.However,at this time,the BM HEAs are in powder state and not easy to be reused,so the loss rate of the powders is high during the reaction.Sometimes,the reaction between reacted the powders and the dye solution is too fast to control.While,in order to solve these problems,this work proposes to immobilize bare BM AlCrFeMn HEA powders in calcium alginate beads(CAB s) by electrospray and microfluidics.Through four cycles of reaction,the loss rate of the AlCrFeMn powders can be reduced from 40 to 5 wt% if the powders are immobilized by CABs with an average diameter of 0.55 mm obtained at the DC voltage of 30 kV.In addition,in the four cycles of experiment,the AlCrFeMn HEA-CABs with an average diameter of0.55 mm shows better stability and easier separation than that of the bare AlCrFeMn powders.These findings provide new ideas for HEAs to decolorize azo dyes and are of great significance for protecting freshwater resources.     

光学材料的磨削损伤控制试验研究

基于K9玻璃不同的磨削工艺参数确定其磨削损伤层深度随工艺参数变化的规律，并通过工件磨削损伤层深度的动态检测研究其裂纹扩展规律。结果表明:工件磨削过程中的裂纹损伤是动态扩展过程。固定工艺参数下，裂纹稳态扩展，损伤层深度不变；采用损伤更小的工艺参数磨削，裂纹的扩展速度小于材料的去除速度，其损伤层深度逐渐减小，损伤的去除速度逐渐减慢直至二者间达到稳态平衡。同时，为了去除前道工序的损伤层，后道工序的材料去除量需达到前道工序损伤层深度的2～3倍。      

烧结温度对Q235钢搪瓷涂层组织结构及性能影响

通过一次涂搪法在 Q235 低碳钢表面制备出 700 ~ 900 ℃ 烧结的搪瓷涂层。 采用 XRD、SEM、EDS、显微维氏硬度计、落球装置及电化学工作站研究了涂层物相组成、组织形貌、微区成分、机械性能及腐蚀行为。 结果表明:搪瓷涂层在烧结过程中表面孔隙率持续减小,截面孔隙率则先减小后增大再减小;磨加物石英逐渐溶解在涂层硅氧四面体 [SiO₄ ]网络中,使涂层显微硬度和光泽度提高;涂层与基体界面处氧化层逐渐减小并最终消失,而 Fe 扩散区逐渐扩大并形成富含 Fe-Co 和 Fe-Ni 枝晶的密着层;涂层表面釉质层形成及内部腐蚀通道的闭合使其耐腐蚀性能显著提高。     

电流驰豫法测试氧化镧掺杂的氧化铈中氧离子迁移

采用甘氨酸-硝酸盐法(GNP)合成了Ce0.65La0.35O1.825(LDC)粉末,在1400℃下烧结10 h得到陶瓷试样,用XRD和SEM表征了样品的物相和表面形貌。用直流电场测试了试样在不同温度下的电流驰豫现象,并计算了不同温度下试样中迁移氧离子数目和材料直流电导率。结果表明,在固态电解质材料中突然施加强电场,可迁移离子基本都发生了位置偏移,但极少部分可以产生长程迁移。随着温度的升高,样品中发生迁移的氧离子数目增加,但都远小于氧空位总量。迁移氧离子数目与温度之间满足阿累尼乌斯公式,其迁移活化能为0.83 eV。     

A novel efficient RhB absorbent of Mo2N/MoO2 composite nanofibers for wastewater treatment

Mo₂N/MoO₂ composite nanofibers have been prepared via an electrospinning and controlled nitridation process. The composite nanofibers exhibit a highly efficient Rhodamine B (RhB) absorption behavior with a rate constant of 0.153 g min⁻¹ mg⁻¹, which is about 20 times of the commercial-activated carbon material. Furthermore, the nanofibers show stable absorption activity after recycled by an environmental friendly procedure for four times. The excellent absorption performance of Mo₂N/MoO₂ composite nanofibers demonstrates a promising application of Mo₂N-related materials as an absorbent for wastewater treatment.