关键词： 纯电动客车   新能源汽车   国家重点研发计划   中通客车   商用车   动力平台   汽车轻量化   能耗降低  

摘要： 2020年10月在上海举行的第14届国际汽车轻量化大会上,中通客车公司推出的镁合金客车LCK 6120 EVQ凭借优良性能荣获中国国轻量化车身会议(商用车)车型优秀奖。早在2017年,中通客车就牵头承担了国家重点研发计划新能源汽车专项项目——"高效纯电动客车动力平台及整车集成关键技术",倾力打造了集轻量化、低成本、高智能、高安全性等性能于一体的镁合金纯电动客车。

关键词： ZK61镁合金   带内筋筒形件   热强旋   感应加热   温度场  

摘要： 对于镁合金带内筋筒形件的热强旋成形,旋前管坯的温度场分布对成形过程中的材料流动及旋压件的成形质量具有重要影响。基于多物理场耦合软件COMSOL,建立了ZK61镁合金带内筋筒形件热强旋旋前管坯电磁感应加热模型,模拟分析了不同感应加热参数条件下管坯温度场的分布情况,并通过实验验证了模型的可靠性。研究结果表明:相比电流强度,电流频率对管坯表心温差的影响更为显著,随着电流频率及电流强度的增加,管坯表心温差均逐渐增大;感应线圈的匝数及线圈与管坯的间距对管坯表心温差的影响较大,随着线圈匝数的增大,管坯表心温差近似呈指数形式增加,线圈与管坯的间距越大,管坯表心温差越小。

关键词： Magnesium alloy   PH   Simulated body fluid   Stress corrosion cracking   LSP/MAO composite Coating  

摘要： Magnesium (Mg) and its alloys are widely used as biodegradable materials in orthopedic applications. However, the poor corrosion resistance of Mg alloys in physiological environments largely limits their application in medical implants. In this study, the surface of AZ80 Mg alloy were modified by two treatment methods, micro-arc oxidation (MAO) and the composition of laser shock penning/micro-arc oxidation technology (LSP/MAO). Slow strain rate tensile (SSRT) testing was performed on untreated (BM) and treated (MAO and LSP/MAO) specimens in simulated body fluid (SBF) with various pH values (4, 7.4, and 9) at a strain rate of 5.3 x 10(-7) s(-1). The scanning electron microscopy (SEM) was used to observe the fracture morphology of corroded specimen. The energy-dispersive X-ray spectroscopy (EDS) was used to analyses elements on corroded surface. The corrosion resistance of different specimens was investigated by electrochemical testing. The results indicated that the MAO specimen itself had the best stress corrosion cracking (SCC) resistance in pH 7.4 SBF, and the worst in pH 4 SBF. The LSP/MAO specimen possessed superior SCC resistance to MAO specimen in SBF with various pH values. The LSP/MAO composite coating can effectively improve the corrosion resistance and mechanical properties of AZ80 Mg alloy, which helps to extend the service life of Mg alloy implants and promote the development of Mg alloys in medical and industrial fields. The SCC mechanisms of three specimens were evaluated in SBF with various pH values.

关键词： 医用金属材料   表面纳米化   生物相容性  

摘要： 医用金属材料具有高强韧性、耐疲劳、易成形和耐腐蚀性等优良性能,既是临床应用最广泛且用量最大的主要生物医用材料,更是需要承受较高载荷的骨、齿等硬组织以及介入治疗支架的首选植入材料。而纳米医用金属材料具有更好的耐蚀性和生物相容性。本文总结了近年临床常用的医用金属材料通过表面纳米化处理带来的性能改变与提升,并对纳米医用金属材料目前存在的问题与发展前景进行讨论。

关键词： TiO2/MgO   Sputtering   Corrosion   In vitro   AZ91D  

摘要： In this study, a coating of thin TiO2 layer and a TiO2/MgO double layer were created on the surface of AZ91D alloy by magnetic sputtering method in order to improve the corrosion and biocompatibility properties of this alloy. The microstructural studies by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) showed that coatings were formed continuously and homogeneously on the alloy surface. In the double-layer coating, MgTiO3 and Mg2TiO4 compounds were formed at the coating/substrate interface in addition to TiO2 and MgO phases as the main phases in the coating structure. The results of corrosion test showed that in general, coating improves the corrosion of AZ91D alloy in simulated-body fluid (SBF). The double-layer coating showed the best corrosion resistance at a corrosion current of 5.743 x 10(-7) mu A/cm(2) and a corrosion potential of -1.513 V due to its cathodic protection of the substrate and blockage of the path of the corrosive solution towards the substrate. In vitro tests showed that considering the good match between the used materials as the coating and body, no toxic material exits which results in improvement in biocompatibility, adhesion, and bone cell multiplication.

关键词： 镁合金   腐蚀   放电性能   锡酸钠添加剂  

摘要： 采用电化学方法探究了不同浓度锡酸钠添加剂对AZ31B镁合金在MgSO 4-Mg(NO 3)2(0.14 mol/L MgSO 4,1.86 mol/L Mg(NO 3)2)电解液中的腐蚀以及电化学放电行为的影响.结果表明,镁合金在含有1 mmol/L锡酸钠添加剂的溶液中具有最大的极化电阻值、最短的滞后时间和最低的电压降.采用电化学阻抗、恒电流放电、线性极化曲线对含有和不含最优浓度锡酸钠添加剂的溶液进行长时间测试,发现在同等浸泡时间内锡酸钠添加剂的引入能够提高镁合金的耐腐蚀能力和放电活性.此外,对浸泡8 d后的两个样品进行扫描电镜,结果表明锡酸钠的加入通过改变镁合金表面形貌来改善镁合金的电化学行为.

关键词： AZ31   Microstructure   LDHs films   Corrosion resistance   Deformation processes  

摘要： Highly oriented Mg-Al layered double hydroxide(LDHs)films were deposited on magnesium alloy AZ31 with different deformation processes by an easy in-situ growth *** characteristics of the films were investigated by optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),and electrochemical,immersion and hydrogen evolution *** corrosion protection performance ranked the LDHs films as the increasing series:CS-LDHs(as-cast sample with LDHs)

关键词： 可控降解速率   降解鎂合金   合金設計  

摘要： 金属材料机械特性优异，适用於生物可降解医用结构型植入物。金属植入物因体液腐蚀，植入物逐渐损失，导致材料腐蚀产物进入到生物体中而可能对生物体产生危害，故生物可降解医用植入物需兼顾金属材料的生物相容性、力学性能及腐蚀性。镁锌钙合金降解後的产物对生物体而言为可代谢且无毒，唯一的缺点为其降解速率难以控制。为了控制镁锌钙合金的降解速率，常藉由添加第四种元素，如铝元素或稀土元素等，但这类元素将伴随着合金降解会残留於生物体中或造成代谢不良的负面影响，因此在临床应用上有安全的疑虑。本研究采用高合金混合熵之镁锌钙合金制备镁合金降解材，并采粉末冶金制程制备，以避免巨观偏析劣化材料，再经由热压成锭後挤制成棒材，经加工後完成可降解镁骨钉制备。

关键词： Mg-Sn合金   热压缩   本构方程   动态再结晶  

摘要： 通过对铸态Mg-3Sn-1Mn-1La合金在变形温度为200~450℃、应变速率为0.001~1.0s^(-1)条件下进行热压缩实验,研究了其热变形行为和微观组织变化规律。结果表明:随着变形温度的降低和应变速率的升高,流变应力明显增大而再结晶晶粒尺寸减小。在变形温度较低的条件下,连续动态再结晶是主要的再结晶机制。然而,当变形温度升高时,非连续动态再结晶机制占主导。分析和修正了摩擦和变形热对流变应力的影响。结果表明,与摩擦相比变形热对流变应力的影响更加明显,且随着应变速率的增加和变形温度的降低,变形热对流变应力的影响更加明显。在实验数据的基础上建立了应变修正的本构方程。通过对实验值与预测值的对比发现,所建立的本构方程能够准确地描述实验合金的热变形行为。

关键词： 地塞米松   聚乳酸羟基乙酸   磁性微球   体外释放   生物相容性  

摘要： 背景磁性微球是近年来出现的一种靶向给药技术,可局部给药,达到控释或缓释效果,减少药物对注射部位的刺激反应,在医学诊断、成像和治疗方面有着广泛的应用。目的制备地塞米松聚乳酸羟基乙酸(poly lactic-co-glycolic acid,PLGA)磁性微球,观察其外观、质量、生物相容性及体外释放等特征。方法制备方法为乳化-溶剂挥发法。质量评价是通过相应方法评估该自制载药微球的外观、跨距、产率、载药量、包封率、体外释放、磁响应性等参数来完成;生物相容性评价则通过检测该自制空白微球的血液及组织相容性来实现。结果该自制微球外观圆整,跨距为(29.66±10.02)μm,产率为(87.25±3.14)%,载药量为(30.33±2.01)%,包封率为(78.89±2.42)%。体外释药模型为Q=4.0844t^(1/2)+6.6602(R^(2)=0.977),其过程无明显突释,第14天的累计释放率为66.99%;磁响应性尚佳。生物相容性检测结果均未见异常。结论该自制PLGA磁性微球质量较好,并有良好的生物相容性。