关键词： WE43 Mg alloy   Self-healing   Inhibitor   Coating   Corrosion  

摘要： Ce(DEHP)3 (cerium tri(bis(2-ethylhexyl)phosphate)) is proposed as a self-healing corrosion inhibitor for WE43. The use of Ce(DEHP)3 in a 3.90 +/- 0.54 mu m hybrid epoxy-silane coating led to an improvement of the coating barrier properties. The presence of the inhibitor increased the corrosion resistance, and Electrochemical Impedance Spectroscopy tests carried out in 0.5 M NaCl revealed low frequency impedance modulus (0.01 Hz) around 10(9) Omega center dot cm(.)(2) The pH-dependant self-healing effect of Ce(DEHP)(3) was evidenced by localized electrochemical techniques, which revealed inhibition of corrosion propagation in artificial defects and decreased net cathodic current densities compared to an unmodified reference coating. Protective behaviour of Ce(DEHP)(3) was related to the combined action of the cerium and organophosphate moieties of this inhibitor, in addition to the protective role of yttrium species derived from the yttrium present in the WE43 magnesium alloy. (c) 2020 Elsevier Ltd. All rights reserved.

关键词： 镁合金   孪晶   弯曲限宽矫直增厚   塑性变形  

摘要： 采用弯曲限宽矫直增厚技术在具有强基面织构的原始AZ31镁合金轧制板中预置拉伸孪晶,研究了弯曲限宽矫直处理前、后镁合金中微观组织和织构的演变及力学性能的变化。结果表明:弯曲限宽矫直处理后合金中的强基面织构被消除,转化为RD方向偏转织构,获得含量为22%的拉伸孪晶界,晶粒尺寸由(11±3)μm减小为(6.4±4)μm;再经过300℃×60 min退火处理后,RD偏转织构强度峰值由7.4降为6.0,晶内仍保留大量拉伸孪晶,晶粒尺寸增加到(7.7±4)μm,其断后伸长率为13.5%,屈强比由轧制态0.63降至0.32,有利于改善塑性,提升镁合金板材的成形性能。

关键词： siRNA delivery   ligand modification   low-molecular-weight polymers   transfection efficiency  

摘要： Incorporating functional ligands and biodegradable bonds into biocompatible low-molecular-weight(LMW)polymers,such as 1.8 kDa poly(ethylenimine)(PEI1.8 k),is a common strategy to improve the properties of LMW polymers including biosafety and delivery *** study demonstrates the hypothesis that introducing different functional ligands and linked reductive disulfides in PEI 1.8k will achieve superior siRNA transfection *** incorporating PEI-X(X represents cholesterol(Ch),heptafluorobutyric anhydride(HFBA,F)and 4-carboxyphenylboronic acid(PBA))functional ligands into PEI 1.8k and subsequently crosslinking with each other via disulfide bond links,reductive-responsive PEI-X-SS-X-PEI copolymers were constructed to enhance the cellular transfection via the synergistic effect of the high affinity of Ch,F and PBA to cell membranes and the disulfide reduction triggered intracellular disassembly of micelles and subsequent siRNA ***,ternary Ch-SS-F-SS-PBA micelles exhibited the strongest siRNA transfection efficiencies in in vitro cell experiments and in vivo animal experiments due to the coordination of enhanced serum stability,promoted cell uptake and endosomal escape,and cell targeting *** strategy of constructed multifunctional polymer here we called"building-block crosslinking"showed a simple and smart way to synthesize new *** this strategy of constructing ligands-directed reduction-sensitive micelles improves the transfection efficiency of LMW PEI and provides a valuable insight to develop novel gene delivery systems.

关键词： 铝合金   镁合金   摩擦搅拌焊接   微弧氧化   析氢实验   电化学交流阻抗分析  

摘要： 摩擦搅拌焊接为近代新发展出的固态焊接技术，虽然有需要施加夹具加压、工件形状无法太复杂等限制，但仍然为铝、镁、钛等金属提供一个快速且高品质的焊接方法。但近期相关研究多着重于焊接后的机械性质的探讨，抑或是同系统合金腐蚀速率的研究，鲜少有探讨异质金属焊接的腐蚀行为和腐蚀机制的建立。本研究探讨两种轻金属AZ31B镁合金与6N01铝合金经摩擦搅拌焊接异质金属接合后的腐蚀速率，并从其腐蚀行为建立其腐蚀机制的模型。同时为了改善其腐蚀抗性耐腐蚀性，对焊接件施加微弧氧化表面处理。本研究中将摩擦搅拌焊接件分为三区:铝母材区(BM-6N01)、镁母材区(BM-AZ31B)和搅拌区(SZ)。借由分析整块焊接件和各区的析氢实验、动电位极化曲线和电化学交流阻抗分析可得知未经微弧氧化表面处理的焊接工件中各区的腐蚀速率由大到小为 SZ > BM-AZ31B > BM-6N01。因为异质金属焊接造成的伽凡尼腐蚀，在阳极的富镁相形成严重的腐蚀，但同时也观察到阴极的富铝相亦受腐蚀。从腐蚀样貌和电化学测量结果推定是因为阳极的富镁相剧烈腐蚀氧化、造成局部酸硷值快速上升，而硷性环境又使得阴极的富铝相的保护层Al2O3/Al(OH)3转化成不具保护性的AlO2-，最终造成富铝相的严重腐蚀。矽酸盐系统的微弧氧化表面处理可同时在搅拌焊接件的三区形成白色陶瓷氧化层，微结构分析显示两种母材区上的氧化层均为上层疏松、下层致密的双层结构，而盐雾试验结果证实此双层陶瓷氧化层可大幅提升抗蚀性。然而，搅拌区的微弧氧化层仍是最易受到腐蚀，显示因为巨观与微观组织与成分的不均匀性，擦搅拌焊接异质金属焊件的表面处理仍是一大挑战。

关键词： 大塑性变形   轧制技术   晶粒细化   织构控制  

摘要： 镁合金大塑性变形轧制技术是一种高性能镁合金板材加工技术,介绍了大塑性变形(SPD)技术原理及新发展起来的几种大塑性变形轧制技术,并对大塑性变形轧制技术进行了展望。

关键词： 镁合金   磁控溅射   氮化铬膜   铬过渡层   膜基结合强度  

摘要： 为了提高磁控溅射氮化铬膜与镁合金基底的结合强度,在两者之间以不同工艺溅射沉积铬过渡层,分析并讨论了铬过渡层对膜基界面结合强度的影响及其机制。结果表明,在镁合金/氮化铬之间增加铬过渡层可提高表征膜基结合强度的膜层破裂临界载荷,且当铬过渡层的溅射工艺为溅射功率100 W、负偏压30 V、基底温度25℃、溅射时间4 min时膜层破裂临界载荷最大,此工艺下铬过渡层表面在微观上具有最大的粗糙度和最小的突起间隔;铬过渡层增强界面结合的作用主要表现为改善了氮化铬与镁合金基底之间的结合状况,与铬/氮化铬接界面积较大且能有效机械互锁、铬过渡层缓减了界面应力等机制有关。

关键词： 血液透析   高通量透析器   个体化心理护理   并发症   生活质量  

摘要： 研究高通量透析器结合个性化心理护理对血液透析患者并发症和生活质量的影响。方法:将2017年3月至2019年1月我院收治的74例血液透析患者按随机数字表分为两组,每组37例。两组均使用高通量透析器进行透析。对照组在透析期间接受常规护理,观察组根据对照组的护理接受个性化的心理护理。比较两组的并发症和生活质量。结果:观察组与对照组相比,并发症发生率较低,干预后SF-36评分较高,差异有统计学意义(P<0.05)。结论:高通量透析器结合个性化心理护理对血液透析患者可以预防并发症并改善生活质量。

关键词： 空分装置冷箱   铝镁合金   管道焊接   质量控制  

摘要： 文章对空分装置冷箱内铝镁合金管道焊接质量控制进行了研究分析。在铝镁合金管道焊接中,严格的材料把控、熟练的操作技术、标准的施工流程、正确的焊接工艺,可以有效提高焊接质量,焊接一次合格率高达99.1%以上。

关键词： AZ80 mg alloy   Annular channel angular extrusion   Heat treatment   Precipitate   Mechanical properties  

摘要： By means of annular channel angular extrusion technology and solution treatment,the AZ80 supersaturated solid solu-tion was ***β-Mg 17 Al 12 precipitate morphologies analysis along with its sizes and area fraction measurement was performed to investigate mechanical properties variation of alloy at various aging *** results indicated that after solution treatment,the intergranular precipitate of as-extruded alloy was re-dissolved into the matrix,eff ectively decreasing the stress concentration,which was benefi cial to the enhancement of *** aging temperatures of 300°C,Widmanstatten structure,lath-shaped precipitate,and intergranular precipitate were observed,while at 175–200°C,cellular structure and oval-shaped particle were also identifi *** morphology,area fraction,size of the precipitates,and PFZs(precipitate free zones)width worked together to aff ect the age-hardening behavior of the *** strength and hardness of the peak-aged samples decreased with the increase in aging temperature,which is primarily attributed to the reduction in cellular structure area fraction and the corresponding increase in the interlamellar spacing,and the coarsening of the rhombus precipitate.

关键词： 镁合金   固溶处理   合金化   耐蚀性  

摘要： 以Mg-1.5Zn-0.5Ca-0.8Ce合金作为研究对象,分别进行合金化和固溶处理,研究Zr的添加及固溶处理对镁合金Mg-1.5Zn-0.5Ca-0.8Ce耐腐蚀性能的影响,并探究合金化和热处理对镁合金耐腐蚀性能影响机理。结果表明:Zr的加入和固溶处理均有效提高了材料的耐腐蚀性,其中Mg-1.5Zn-0.5Ca-0.8Ce-0.7Zr镁合金固溶试样具有最优异的耐腐蚀性能。研究表明合金化及热处理对镁合金的组织和耐腐蚀性均具有重要影响。