海底用喷涂聚氨酯硬泡保温配重管的节点补口技术

针对海洋油气输送用聚氨酯硬泡喷涂保温配重管铺设过程中节点补口进行改进研究,介绍了一种聚氨酯硬泡喷涂保温配重管节点结构和施工工艺。主要采用聚氨酯硬泡保温半瓦和浇注聚氨酯弹性体进行节点补口,节点补口性能测试验证效果良好,满足海底油气管道铺设要求。     

全球连续铸轧生产铝汽车板专利技术发展态势分析

随着汽车轻量化策略的持续推进,作为汽车车身应用轻量化材料的铝合金板已成为汽车轻量化领域的研发重点,而连续铸轧技术是生产汽车车身铝板较为先进的技术之一。本文通过收集德温特创新索引国际专利数据库(DII)、普若凯斯特专利数据库(Proquest Dialog)等涉及连续铸轧生产铝汽车板的专利,利用汤姆森数据分析软件(Thomson Data Analyzer)等主流情报分析工具,对连续铸轧生产汽车板技术在全球的研发现状、态势及主要技术方向,以及美国铝业公司连续铸轧生产铝汽车板专利发展态势进行分析。     

飞机蒙皮材料在醋酸钾型除冰液中腐蚀行为研究

目的 评价醋酸钾型除冰液能否用于飞机除冰以及对飞机蒙皮材料腐蚀性的影响。方法 采用AutoLab电化学工作站对飞机蒙皮材料在不同浓度缓蚀剂、无缓蚀剂醋酸钾型除冰液中的干湿交替腐蚀电化学行为进行分析，通过扫描电镜观察其腐蚀前后表面形貌及涂层/基体金属界面形貌。结果 无缺陷飞机蒙皮涂层在除冰液中的阻抗模值高达2.78×1010 Ω?cm2，而缺陷涂层的阻抗模值只有1.72×107 Ω?cm2，说明缺陷破坏了涂层的完整性，降低了涂层的阻抗模值，明显加速了飞机蒙皮材料的腐蚀。带缺陷飞机蒙皮试样经除冰液腐蚀不同周期后的低频区Rct存在较大变化，试样在高浓度无缓蚀剂除冰液中的Rct始终低于在低浓度溶液中的Rct；试验初期，试样在高浓度除冰液中的Rct较大，说明此时缓蚀剂浓度较高，缓蚀作用明显；但随着腐蚀周期的延长，Rct逐渐减小，说明缓蚀剂逐渐失效，高浓度除冰液的腐蚀性逐渐增强并高于低浓度除冰液。腐蚀实验后，飞机蒙皮涂层表面和涂层/基体金属界面处存在一定的腐蚀产物；人造缺陷破坏了涂层的完整性，降低了涂层的结合力，甚至产生局部剥离，造成除冰液浸入，在划痕处发生了较严重的膜下腐蚀。结论 醋酸钾型除冰液对飞机蒙皮材料存在一定的腐蚀性，尤其是当涂层存在缺陷时，腐蚀较为严重。     

一种振动矢量测量及调整的方法

针对消失模生产中振实设备的振动过程不满足工艺要求的情况下会产生的问题,详细阐述了基于消失模振实、紧实过程的测量方法和评价方法,通过使用该种方法可以得出振动矢量和振幅,进而对振实紧实设备和振动紧实工艺进行调整和优化,杜绝干砂振动紧实过程中的各种问题,保证铸件质量。可以普遍应用在干砂振实设备研发、校检、定期维护等各个过程,可以有效提升设备的工艺符合性,减少模样及铸件不合格品的产生。     

时效时间对7150铝合金组织和性能的影响

通过维氏硬度测试、电导率测试和拉伸、晶间腐蚀等测试方法,研究了预时效、回归及再时效三个阶段中的时效时间对7150铝合金组织和性能的影响,借助透射电镜观察时效处理各阶段合金的微观组织演变。结果表明:120℃×20 h欠时效作为预时效工艺,比120℃×24 h峰时效的晶内析出相更细小,高温回归时更利于回溶。在190℃短时回归5、15和30 min中,15 min回溶效果最好,硬度最低,再经120℃×24 h再时效后合金抗拉强度Rm、屈服强度RP0.2、伸长率A分别为622 MPa、573 MPa、10.8%,显微硬度为204 HV,力学性能与120℃×24 h单级峰时效时相近。经120℃×20 h+190℃×15 min+120℃×24 h处理后7150铝合金综合性能好,耐晶间腐蚀性能佳。     

铸态及退火态Mg66Al34阳极镁空气电池的性能

制备了铸态及退火态Mg66Al34共晶合金,通过研究该合金的腐蚀及放电行为,考察了该合金作为镁空气电池阳极的放电性能。结果表明:在3.5 mass%NaCl溶液中,铸态合金具有较低的腐蚀速率及放电活性,退火态合金具有高的腐蚀速率及放电活性。在NaCl溶液中加入水溶性石墨烯后,铸态合金具有低的腐蚀速率及较高放电活性。铸态合金低的腐蚀速率是由于在β-Mg17Al12层间形成了黑色富铝氧化物腐蚀产物。     

Phase field lattice Boltzmann model for non-dendritic structure formation in aluminum alloy from LSPSF machine

The formation of non-dendritic structures in the primary phase of an aluminum alloy solidified using low superheat pouring with a shearing field (LSPSF) machine was investigated by numerical simulation. The growth and motion of a dendrite during solidification was simulated by a combination of the lattice Boltzmann method and the phase field method. The simulation results indicated that enough shear flow helped homogenize the concentration fields, rotate crystals and altere microstructures from dendritic to non-dendritic. The interaction of grains was also discussed. A fragmentation criterion was established based on partial remelting of dendrite arms; fragmentation was enhanced by a strong shear flow and larger inclined angles. The simulation results were verified experimentally.     

Microstructure,mechanical and wear properties of aluminum borate whisker reinforced aluminum matrix composites

The microstructural features and the consequent mechanical properties were characterized in aluminium borate whisker (ABOw) (5, 10 and 15 wt.%) reinforced commercially-pure aluminium composites fabricated by conventional powder metallurgy technique. The aluminium powder and the whisker were effectively blended by a semi-powder metallurgy method. The blended powder mixtures were cold compacted and sintered at 600 °C. The sintered composites were characterized for microstructural features by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. Porosity in the composites with variation in ABOw contents was determined. The effect of variation in content of ABOw on mechanical properties, viz. hardness, bending strength and compressive strength of the composites was evaluated. The dry sliding wear behaviour was evaluated at varying sliding distance at constant loads. Maximum flexural strength of 172 MPa and compressive strength of 324 MPa with improved hardness around HV 40.2 are obtained in composite with 10 wt.% ABOw. Further increase in ABOw content deteriorates the properties. A substantial increase in wear resistance is also observed with 10 wt.% ABOw. The excellent combination of mechanical properties of Al−10wt.%ABOw composites is attributed to good interfacial bonds, less porosity and uniformity in the microstructure.     

Viscosity of glass-forming melt at the bottom of high-level waste melter-feed cold caps: Effects of temperature and incorporation of solid components

During the final stages of conversion of melter feed (glass batch) to molten glass, the glass-forming melt becomes a continuous liquid phase that encapsulates dissolving solid particles and gas bubbles that produce primary foam at the bottom of the cold cap (the reacting melter feed in an electric glass-melting furnace). The glass-forming melt viscosity plays a dominant role in primary foam formation, stability, and eventual collapse, thus affecting the rate of melting (the glass production rate per cold-cap area). We have traced the glass-forming melt viscosity during the final stages of feed-to-glass conversion as it changes in response to changing temperature and composition (resulting from dissolving solid particles). For this study, we used high-level waste melter feeds—taking advantage of the large amount of data available to us—and a variety of experimental techniques (feed expansion test, evolved gas analysis, thermogravimetric analyzer-differential scanning calorimetry, X-ray diffraction, and viscometer). Starting with a relatively low value at the moment when the melt connects, melt viscosity reached maximum within the primary foam layer and then decreased to its final melter operating temperature value. At the cold-cap bottom—the boundary between the primary foam layer and the thermal boundary layer—where physicochemical reactions of a melter feed influence the driving force of the heat transfer from the melt to the cold cap, the melt viscosity affects the rate of melting predominantly through its effect on the temperature at which primary foam is collapsing.     

液态CO2辅助喷涂发泡聚氨酯硬泡的研究

采用三组分聚氨酯硬泡喷涂高压发泡机,以HCFO-1233zd(E)或HFO-1336mzz(Z)为主体发泡剂,将液态CO2作为第三组分添加,制备了喷涂聚氨酯硬泡。对比了不同含量CO2喷涂发泡制得的聚氨酯泡沫制品的性能。结果表明,添加液态CO2会使泡沫的乳白时间缩短,凝胶时间和固化时间延迟;添加适量液态CO2可以提高泡沫制品的压缩强度,能降低泡沫的闭孔率;添加少量液态CO2会使泡沫的泡孔分布更加均匀,泡沫更加细腻,可以提高HFO类发泡体系泡沫的综合性能,尤其能提高泡沫超低温环境下的绝热性能。