防腐管道喷砂预处理表面形貌及硬度分析

以石英砂、铁砂为原材料,进行垂直喷砂和倾斜45°喷砂工艺探索。利用扫描电镜对比观察显微组织形貌,结合能谱仪分析取样点处的化学成分。结果表明,垂直喷砂形成大而深呈圆形麻坑。倾斜喷砂产生细小的滑痕和由浅变深的椭圆形麻坑。垂直喷砂更有利于增加材料表面的粗糙度,而斜喷时更有利于除锈。喷铁砂后表面获得的残余应力比喷石英砂更大。经过喷砂处理后管道表面的硬度值均有所提高。     

超声冲击改善奥氏体不锈钢表面状态的数值分析

基于Johnson-Cook方程建立超声冲击处理的三维有限元模型,研究超声冲击处理奥氏体不锈钢S30408的动力学过程,分析覆盖率、搭接率、冲击次数对表层残余应力分布、塑性变形及形貌的影响。结果表明,覆盖率的增加提高了冲击处理后材料表面的压应力值,同时降低了冲击坑边缘的最大拉应力值。进一步增加覆盖率无法消除表面的残余压应力高值区域,但是通过提高冲击处理的搭接率可以有效地降低材料的表面拉应力,从而显著提高处理后S30408材料的表面质量。     

几种机械表面处理方法对6013铝合金接头胶接性能的影响

采用砂纸打磨、湿喷砂、纳米化等3种机械处理方法对6013铝合金表面进行处理,测试其粘接剪切强度,并与P2化学表面处理方法的结果进行对比。利用SEM、AFM、接触角测量仪等技术对铝合金表面处理前后的表面微观结构、微观粗糙度、润湿性等特性进行了研究。结果表明,不同的表面处理方法对铝合金接头的胶接性能影响不同。湿喷砂和砂纸打磨方法处理后铝合金接头的胶接性能与P2化学法表处的效果接近。纳米化方法不利于铝合金胶接性能的提高。微观粗糙度对铝合金的粘接性能具有重要影响,粗糙度越大,铝板胶接性能越好。润湿性不是影响胶接性能的关键因素。     

Al2O3陶瓷表面加工残余应力的研究

讨论了四种不同的工艺对Al2O3-TiC复相陶瓷进行表面处理，以改变其表面残余应力分布状态。利用扫描电子显嫩镜(SEM)观察试样的表面形貌；采用非破坏性的X射线衍射sin^2ψ法，对不同工艺条件下的残余应力进行了测试研究。结果表明：在本研究条件下，经平面磨处理后．试样表面赴于拉应力状态；经工具磨处理后，试样表面处于压应力状态；经抛光处理后，残余应力值均有所减小。这对于提高陶瓷材料的强度和耐磨性具有重要的意义。     

Al2O3-TiC复相陶瓷表面残余应力的研究

本论文应用4种不同的工艺对Al2O3-TiC复相陶瓷进行表面处理,以改变其表面残余应力分布状态。利用扫捕电子显微镜(SEM)观察试样的表面形貌;采用非破坏性的X射线衍射法,对不同工艺条件下的残余应力进行测试研究。结果表明：在本研究条件下,经平面磨处理后．试样表面处于拉应力状态;经工具磨处理后,试样表面处于压应力状态;经抛光处理后,残余应力值均有所减小、这对于提高陶瓷材料的强度和耐磨性具有重要的意义。     

基体残余应力对铝合金热控膜层的影响研究

本文研究了基体残余应力对铝合金热控膜层的影响,测试了不同热处理条件下2A12铝合金基体的残余应力,通过扫描电子显微镜对膜层的微观结构进行了分析,并对阳极氧化膜与基体结合强度及膜层的裂纹扩散进行了研究,分析了涂层残余应力形成机理。结果表明,铝合金消应力退火处理可以减轻阳极氧化膜的裂纹扩展情况。     

磷酸–硫酸阳极氧化对铝合金表面粘接性能的影响

研究了磷酸–硫酸阳极氧化对铝合金2A50表面粘接性能的影响,并与喷砂处理进行比较。阳极氧化液组成与工艺条件为:磷酸70g/L,硫酸50g/L,草酸7g/L,甘油20g/L,温度(22±2)℃,电压20V,时间35min。采用扫描电镜观察经阳极氧化处理和经喷砂处理的铝合金表面、粘接界面、破坏界面的微观形貌,利用能谱仪分析阳极氧化膜的组成。结果表明,磷酸–硫酸阳极氧化可明显提高铝合金粘接副的拉伸剪切强度和粘接耐久性能。分析了磷酸–硫酸阳极氧化的成膜特点及电解液主要成分的作用,解释了阳极氧化处理后铝合金的粘接性能优于喷砂处理的原因。     

树脂预浸润技术(RPC)增强钢塑复合管道层间粘接性能研究

围绕钢塑复合管道材料中钢和塑料粘接界面的性能强化,提出在喷砂、锉刀压痕等物理磨损处理提高基体表面粗糙度的基础上,结合环氧树脂预浸润技术(RPC)对粘接基体进行表面处理.实验结果表明,结合了喷砂和锉刀压痕以及RPC处理的钢-尼龙粘接材料试样,单面搭接剪切法(SLS)测试剪切强度最大提升率达68.28％.     

高速动车组铝合金车辆的防腐蚀初探

根据制造高速动车组铝合金材料腐蚀的特点,以阻止和延缓腐蚀的产生为目标,设计结构充分考虑铝合金车体结构的防腐需要,同时表面处理采用不含铁的三氧化二铝材料进行喷砂,防腐底漆采用不含铁质颜料的双组分环氧底漆以及与之相配套的双组分油漆涂装保护体系对高速动车组车辆进行防腐涂装,为铝合金车辆的防腐蚀探索出了切实可行的措施,同时提供了标准的防腐涂装配套保护体系。     

直升机桨叶包片胶接前激光毛化处理的有效性研究

为提升直升机桨叶包片胶接质量,开展激光毛化技术在不同材料包片胶接前表面处理工艺中的有效性研究.分别对经酸洗、喷砂、激光毛化工艺处理后的钛合金、不锈钢、纯镍金属材料试件,进行外观、粗糙度、微观形貌检测,并在胶接后进行浮辊剥离试验、剪切强度试验,结果表明:激光毛化处理可在金属表面获得规则的微观形貌,且试件无变形现象,与喷砂表面同等级粗糙度下,浮辊剥离值及剪切强度明显高于喷砂或酸洗处理的表面,可有效提升胶接结合强度.     

Effect of surface nucleation on isothermal crystallization kinetics: Theory, simulation and experiment

Surface nucleation of poly(l/d-lactide) at the interface with aluminum was studied by performing isothermal DSC analysis of amorphous samples of varying thickness between 100 °C and 130 °C. To ensure complete wetting of the aluminum surface, a hot melt laminating process was used to prepare the samples. Theoretical aspects of surface crystallization kinetics were explored and the resulting model was compared with the results of Monte-Carlo simulations. Three stages of surface crystallization were identified depending on the growth geometry: (1) impingement-free growth, (2) increasingly laterally-constrained transverse growth, and (3) interstitial growth. By fitting the Monte-Carlo simulation to the experimental half-times of crystallization the surface nucleation concentration and the bulk nucleation rate was estimated at 4 different temperatures. It was found that both surface nucleation concentration and the bulk nucleation concentration decrease with increasing crystallization temperature.     

Influence of aluminum alloys on protection performance of metal matrix composite armor reinforced with ceramic particles under ballistic impact

In this research, the ballistic performance of three series of aluminum alloys in the ceramic-reinforced metal matrix composite plates is investigated for protecting against 7.62 × 39 mm bullet. Twenty seven numerical models of the target combinations are provided by ABAQUS FE code to determine the best armor characteristics and confirmed by three experimental ballistic tests. The parameters which considered in this study are aluminum alloys: AA6061, AA7075 and AA5083 as the matrix, alumina ball weight percentages include 15%, 30% and 45% as reinforcements and the target thickness 20, 25 and 30 mm and the effects of these parameters on the ballistic behavior of the composite armor like depth of penetration, residual velocity, kinetic energy and erosion of the projectile are investigated. The results show that AA6061 is the weakest aluminum alloy for ballistic applications and AA5083 is the best choice to use as the aluminum matrix. Also, it's found that the optimum design of aluminum matrix composite armor against 7.62 × 39 mm projectile is AA5083 with 25 mm thickness and 30% alumina.     

防锈铝合金及锻铝合金的焊接

通过对防锈铝合金5083和锻铝合金6061的焊接性进行分析,并针对焊接中容易出现的缺陷制定了相应的措施,最终成功的完成了铝合金设备的安装。     

铝空气电池用6061和7075铝合金阳极电化学性能

研究了工业6061铝合金（6061）、航空7075铝合金（7075）和纯铝作为铝空气电池阳极材料的电化学性能,分析其作为阳极的可行性及适用环境。进行了阻抗、极化曲线和恒电流放电实验并进行了表面表征,计算了在40～120mA/cm²电流密度下连续恒流放电的阳极能量密度。用电子探针显微镜（EPMA）对电极表面形貌进行了研究,用波谱分析仪（WDS）进行表面分析。研究结果表明,合金元素在电池放电过程中会改变阳极的表面特性。6061中合金元素含量对电池阳极材料的性能产生了积极影响,使得合金的表面放电面积变大,放电均匀,更适合作为铝空气电池阳极材料。     

有机杂环化合物对铝合金在3.5%NaCl介质中的缓蚀作用

添加有机缓蚀剂可以减缓或防止铝合金在3.5%NaCl溶液中的腐蚀。用失重法和电化学法分别研究了7种有机化合物对7075铝合金在3.5%NaCl溶液中的缓蚀行为,并用扫描电子显微镜(SEM)对铝合金样品在不同缓蚀介质中的腐蚀形貌进行了观测。失重法实验结果和Tafel极化测试结果均表明,这些有机化合物对铝合金有不同程度的缓蚀作用,其中7-氮杂吲哚的缓蚀效果最好,通过对铝合金样品表面孔蚀特征及电化学测量结果的分析,确定其缓蚀机理为阳极过程控制为主的成膜缓蚀剂。     

Effect of heterocyclic organic inhibitors on corrosion behavior of aluminum in 3.5% sodium chloride solution

添加有机缓蚀剂可以减缓或防止铝合金在3.5%NaCl溶液中的腐蚀。用失重法和电化学法分别研究了7种有机化合物对7075铝合金在3.5%NaCl溶液中的缓蚀行为,并用扫描电子显微镜(SEM)对铝合金样品在不同缓蚀介质中的腐蚀形貌进行了观测。失重法实验结果和Tafel极化测试结果均表明,这些有机化合物对铝合金有不同程度的缓蚀作用,其中7-氮杂吲哚的缓蚀效果最好,通过对铝合金样品表面孔蚀特征及电化学测量结果的分析,确定其缓蚀机理为阳极过程控制为主的成膜缓蚀剂。     

Novel approach using EIS to study flow accelerated pitting corrosion of AA5083-H321 aluminum–magnesium alloy in NaCl solution

EIS was utilized as a novel approach to study the role of mechanical and electrochemical processes in flow accelerated pitting corrosion behaviour of AA5083-H321 aluminum–magnesium alloy in 3.5% NaCl solution. This alloy is a suitable material for manufacturing of high speed boats, submarines, desalination systems etc. Impedance spectra were obtained during 24 h of exposure of the samples to the test solution at different rotation speeds. The surface and cross section of the samples were studied by scanning electron microscopy (SEM) and EDAX analysis. The results indicated that increasing the rotation speed causes the depth of pits to increase. By further increasing the rotation speed to 5 and 7 m s⁻¹, the flow condition causes the passive layer inside the pits to breakdown. Simultaneously, the thickness of the passive layer on the areas other than the pits becomes thinner. Shear stresses at 10 m s⁻¹ are so severe that the passive layer on the entire surface breaks down and leads to micropitting corrosion.     

Comparison of AC to DC current sources for field-assisted sintering of aluminum alloy 5083 powder

The viability of resistively sintering aluminum 5083 powder with an alternating current (AC) was explored under both as-atomized and cryomilled conditions. Samples were processed under an AC field and a direct current (DC) field. Samples processed by both methods exhibited similar microstructures and densities at different die wall temperatures. For as-atomized powders, similar densities (99% of theoretical [TD]) were achieved at die wall temperatures of 564°C under DC fields and 525°C under AC fields. For cryomilled 5083, densities up to 90% of theoretical were achieved at 550°C under DC fields, while density values 99% of TD were achieved at 500°C under AC fields. Based on these findings, it has been determined that AC fields can be used as an alternative to SPS for achieving optimal density.     

Tribological and mechanical characteristics of AA5083 alloy reinforced by hybridising heavy ceramic particles Ta2C & VC with light GNP and Al2O3 nanoparticles

In this study, AA5083 sheets were reinforced with four different hybrid nanoparticles by friction stir processing (FSP) for the development of surface nanocomposites used in advanced engineering applications. The present research focused on improving the properties and tribological behaviour of AA5083 alloy surfaces, including novel hybrid nanoparticles and the intermetallic phase formed during FSP. A tribometer tester with a constant normal load was used to examine the tribological performance of the hybrid composites. After the wear test, a surface profiler inspector was used to analyse the morphology and surface roughness of the examined materials. The Vickers micro-hardness of the base metal and the manufactured composites were measured. During FSP, a new intermetallic phase of AlV₃ was successfully formed at 300–400 °C in the hybrid nanocomposites containing VC particles. The reinforcements resulted in additional grain refining than FSP. The AA5083/Ta2C–Al₂O₃ exhibited the greatest grain refinement, a sixty-fold reduction in grain size compared to that of the base alloy. The results revealed that the hybrid nanocomposites containing VC particles demonstrated the most significant microhardness values inside the stirred zone as a result of the presence of the AlV₃ phase, which was increased by 25–30%. Moreover, the mechanical properties were significantly improved for all manufactured nanocomposites. The tensile strength was increased by 28% through the hybridisation of AA5083 using a hybrid of VC-GNPs. The dispersion of Ta₂C-GNPs and VC-GNPs in the matrix led to excellent interfacial adhesion, resulting in an enhancement in the mechanical properties. The AA5083/VC-GNPs surface composite outperformed other manufactured composites regarding wear resistance. In addition, due to GNPs soft nature, it reduced the coefficient of friction (COF) of the manufactured composites by 20–25% compared to other reinforcements.     

Ice adhesion on different microstructure superhydrophobic aluminum surfaces

The adhesion of ice to high -voltage overhead transmission lines should be small to ensure ease of ice shedding under small external forces. In this work, we studied the influence of the microstructure of superhydrophobic surfaces on the strength of ice adhesion at a working temperature of ?6?°C. Compared to a bare aluminum surface, the microstructure superhydrophobic aluminum surfaces did decrease ice adhesion strength. The superhydrophobic aluminum surfaces with a larger number of micro-holes produced the lowest strength of ice adhesion; its ice adhesion strength was ～163.8 times lower than that for the bare aluminum samples. Furthermore, such microstructure aluminum surfaces had water contact angles larger than 150° and water sliding angles of less than 8.2° even at a working temperature of ?6?°C. The low values of the ice adhesion strength of the above samples were mainly attributed to the superhydrophobic property, which was obtained by creating a structure of micro-nanoscale holes on the aluminum surface after treatment with a low- surface-energy fluoroalkylsilane (FAS).