WC-10Co纳米复合粉末棒材的成型工艺研究

研究了WC-10Co纳米复合粉末的模压、挤压成型及冷等静压复压工艺.用SEM观察了生坯的显微结构.结果表明:运用本研究优化的模压、挤压工艺能生产出合格的棒坯;模压成型后的冷等静压处理工艺可以减少坯体孔隙度,提高其强度,但冷等静压处理工艺对挤压成型的坯体的后期效果并不明显.     

不同烧结气氛制备AZO靶材的实验研究

采用机械混粉、造粒、模压和冷等静压(CIP)成型相结合的功能陶瓷制备工艺制备了AZO靶材,研究了空气、真空及惰性气氛对AZO靶材性能的影响.结果发现,氩气保护烧结法制备的AZO靶材不仅密度高,电阻率达10-4Ω·cm量级,而且该方法还可明显抑制氧化锌的挥发,降低烧结温度,在1320℃的温度下便可制得相对密度为99％、晶...     

不锈钢粉末冷等静压数值模拟与实验验证

通过冷等静压实验获得了不锈钢粉末的压力-密度关系,在模拟中用于表征材料的硬化特性。为了描述粉末的致密化行为,使用了ABAQUS有限元软件中的Cam-Clay模型,对粉末的冷等静压实验过程进行模拟,结果表明实验的尺寸与模拟的结果符合得较好,说明模拟中使用的参数设置是合理的。然后使用选择性激光烧结/冷等静压复合工艺制造球形制件,并对冷等静压过程进行模拟,结果表明制件变形比较均匀,实验的结果与模拟的结果符合得较好,密度的预测与实验结果比较吻合。通过模拟不仅为冷等静压工艺提供有益的指导,也为以后复杂试样的冷等静压尺寸设计提供了重要参考。     

等静压辅助凝胶注模成型制备高致密Ba0．7Sr0．3TiO3陶瓷

采用凝胶注模成型制备了Ba0.7Sr0.3TiO3陶瓷坯体.为了提高陶瓷的致密度,对干燥后的坯体进行了冷等静压处理.研究结果表明:冷等静压压力为100MPa时,坯体的机械强度从29.6MPa提高到32.8MPa,陶瓷的相对密度从无压时的96.4%增加到98.2%.等静压辅助凝胶注模成型制备的陶瓷相对于传统等静压法制备的陶瓷,晶粒小而均匀,结构致密,是一种理想的制备功能陶瓷材料的新方法.     

曲面薄壁钛合金铸件变形工艺控制研究

目的 研究曲面薄壁钛合金铸件变形规律及发生的阶段,提出防止变形的工艺措施。方法 通过对出气管铸件成形过程进行计算机模拟仿真,对蜡模、浇注成形后的铸件、热等静压后的铸件进行扫描拟合,分析了出气管在蜡模压制、铸造成形、热等静压过程中的变形,提出了控制蜡模变形和铸件热等静压过程变形的工艺措施,并进行了试验验证。结果 出气管蜡模在压制和放置过程中,远端浇口连接处发生翘曲变形,变形量约0.5 mm;铸件在无约束的热等静压过程中,发生扭曲变形,变形量约0.5 mm,蜡模变形和热等静压过程变形叠加,导致铸件变形约1 mm。结论 计算机模拟仿真可以有效缩短铸件研制过程,获得优质铸件;增加蜡模胎膜和约束下铸件热等静压,可以有效控制铸件变形,获得合格铸件。     

废旧线路板粉料/玻璃纤维增强复合材料研制

以废旧线路板回收处理过程中得到的塑料粉料与玻璃纤维作为增强材料,采用模压成型的方法制备成不饱和聚酯复合材料。研究了模压工艺参数以及废弃物粉末填料配比等对复合材料力学性能的影响规律,并初步展望了废弃物复合材料的应用。结果表明,随着模压温度、压强、模压时间和填料含量的增加,复合材料的弯曲强度先升高后降低;在优化的模压工艺参数条件下,用废弃粉体与短切玻璃纤维作为组合增强体,制得的不饱和聚酯复合材料的力学性能远大于仅用废弃粉体作为增强体的力学性能,其弯曲强度和冲击强度可达150MPa、18kJ/m2。     

一种CL-20基混合炸药等静压装药工艺安全性分析

为确保炸药在等静压装药工艺过程中的安全性,对一种CL-20基混合炸药(GMD-15)的本质安全性及其与接触材质的相容性进行了分析;运用数值模拟、力学性能测试、热安全性能测试手段,重点分析了GMD-15等静压压制工艺过程中的受力安全性以及热安全性。数值模拟表明:140 MPa条件下,等静压压制药柱的温升为7℃,小于普通模压(29℃);力学性能测试中以≥5 MPa/s的应力率对GMD-15药柱施加压应力,药柱没有发生爆炸或者燃烧;热安全性能测试中以1.5~2.0℃/min的升温速率对GMD-15药粉进行加热,190℃药粉方发生反应,将GMD-15药柱在108℃左右恒温3 h,未发生反应。分析认为,等静压压制GMD-15工艺过程安全,不会导致炸药发生热爆炸。     

Y_2O_3含量及制备工艺参数对Y－TZP纳米粉烧结体性能的影响

用化学共沉淀法制备了Ｙ２Ｏ３含量不同的两种Ｙ－ＴＺＰ纳米粉体；采用不同压力下冷等静压成形制备素坯；研究Ｙ２Ｏ３含量、素坯成型压力及烧结温度对Ｙ－ＴＺＰ陶瓷体密度、组织结构及机械性能的影响。     

工艺条件对高性能石英砂烧结砖的显微结构影响研究

本文研究了利用低品位石英砂在不同工艺条件下制备的高性能石英砂烧结砖的显微结构,并通过显微结构与成型方法、成型压力、烧结温度及保温时间的关系分析,确立该烧结砖得到最高性价比时的最佳工艺条件.结果表明:该烧结砖采用100MPa冷等静压成型,在1150℃烧结2h的制备工艺所得的砖的显微结构最佳.     

凝胶注模成型制备高性能的氮化硅陶瓷(Ⅱ)-冷等静压、粉料氧化处理和气压烧结对材料性能的影响

在对氮化硅粉料进行助烧剂包覆和凝胶注模成型的基础上,研究了冷等静压凝胶注模成型氮化硅坯体、氧化氮化硅包覆料和气压烧结制度对凝胶注模成型氮化硅陶瓷的抗弯强度和韦泊尔模数的影响冷等静压有利于提高凝胶注模成型氮化硅陶瓷的力学性能.合适的粉料氧化制度和烧结制度都能提高材料的抗弯强度和韦泊尔模数.实验采用优化的工艺,制备出的氮化硅陶瓷的三点弯曲强度和两参数韦泊尔模数(20个试样)分别高达944.7±29.5MPa和33.9.     

氧化锌铝(ZAO)靶材的制备及性能研究

采用冷等静压成型(CIP)、低真空烧结和热等静压(HIP)烧结技术制备ZAO靶材,采用排水法、SEM、XRD、光谱发射法(ICPOES)分析了2种烧结方法制备的ZAO靶材的密度、结晶状态和组织成分.结果表明,ZAO细粉经压力造粒后,CIP成型压坯相对密度可达75%以上,该压坯经低真空高温烧结,相对密度达到95%,而采用HIP低温烧结的靶材可达到98%以上,靶材结晶完整,组织成分均匀.     

基于SLS/CIP工艺SiC陶瓷的制备及其性能

以喷雾干燥的SiC-Al_2O_3-Y_2O_3造粒粉为原料,使用机械混合法得到复合粉体,通过激光选区烧结/冷等静压技术并结合液相烧结工艺制备出SiC陶瓷,对SiC陶瓷的物相组成、显微结构、抗弯强度及密度进行表征。结果表明:喷雾造粒粉平均粒径为39.43μm,球形度较高,流动性良好,适用于SLS成型;SLS成型最优参数为激光功率7W、扫描间距0.15mm、扫描速率2200mm/s、单层层厚0.15mm且CIP压力为80MPa时, SiC陶瓷素坯的性能最佳,抗弯强度为(2.23±0.10)MPa,密度为(1.31±0.05)g/cm^3;在1950℃下烧结2h后,样品发生了致密化,SiC陶瓷密度为(1.95±0.17)g/cm^3,相对密度为(60.81±5.31)%,抗弯强度为(55.43±4.04)MPa。     

Consolidation behavior of L12 phase (Al + 12.5 at.% Cu)3Zr powder with nanocrystalline structure during CIP and subsequent sintering

The mechanically alloyed (Al + 12.5 at.% Cu)₃Zr powders were consolidated by cold isostatic pressing (CIP) and subsequent sintering. Effects of CIP pressure and sintering temperature on the stability of metastable L1₂ phase and nanocrystalline structure were investigated. Before sintering, the powders were CIPed at 138, 207, 276, and 414 MPa. The relative densities of the CIP compacts were not greatly affected by the CIP pressure. However, the L1₂ phase of the specimen CIPed at pressures greater than 276 MPa was partially transformed into D0₂₃. The optimum consolidation conditions for maintaining L1₂ phase and nanocrystalline microstructure were determined to be CIP at 207 MPa and sintering at 800 °C for 1 h for which the grain size was 34.2 nm and the relative density was 93.8%. Full density specimens could be prepared by sintering above 900 °C, however, these specimens consisted of L1₂ and D0₂₃ phases. The grain sizes of all the specimens were confirmed by TEM and XRD, and were found to be less than 40 nm. This is one of the smallest grain sizes ever reported in trialuminide intermetallic compounds.     

数值模拟在氧化铝陶瓷SLS/CIP过程中的应用

采用选择性激光烧结(SLS)和冷等静压(CIP)复合工艺制造高密度形状复杂的氧化铝零件,经高温烧结,氧化铝零件密度高达94.5%.应用修正的Cam-Clay模型模拟了零件的CIP过程,同时通过模拟和实验研究其在CIP过程中的致密化、变形及收缩规律.研究表明,在激光扫描平面内模拟与实验的尺寸相对误差不超过2.26%,证明该模拟可为氧化铝SLS零件的尺寸设计和CIP过程提供有利指导.     

Comparison between slip-casting and uniaxial pressing for the fabrication of translucent yttria ceramics

Slip casting and uniaxial pressing were compared as first consolidation stages prior to cold isostatic pressing (CIP) to produce translucent yttria ceramics. In the first step, yttria slurries suitable for slip casting were prepared. The viscosity was optimized with respect to the starting agglomeration state, amount of dispersant, milling time, and number of milling balls. Secondly, pellets were prepared either by slip casting or uniaxial pressing and then cold-isostatically pressed. Finally, the pellets were made translucent by a combination of pre-sintering and hot isostatic pressing (HIP). Although slip-cast and pressed samples exhibited similar green-body densities after CIP and pre-sintering, the samples prepared by slip casting were more homogeneous in terms of translucency and microstructure throughout their bodies. This was attributed to the ability of slip casting to minimize density gradients during packing, and to the beneficial effect of ball-milling to remove larger agglomerates before casting. Therefore, slip casting as a first consolidation stage prior to CIP appears to be more suitable than uniaxial pressing in order to prepare homogeneous optical ceramics.     

Discrete element modeling and experimental investigation of hot pressing of intermetallic NiAl powder

This paper presents the numerical and experimental analysis of hot pressing of NiAl powder with an emphasis on the best possible representation of its main stages: initial powder compaction and pressure-assisted sintering. The numerical study has been performed within the discrete element framework. In the paper, an original viscoelastic model of hot pressing has been used. In order to ensure that the applied values of material parameters in numerical simulations are appropriate, the reference literature has been reviewed. It produced the relations and equations to estimate the values of all required sintering material parameters of the considered viscoelastic model. Numerical simulations have employed the geometrical model of the initial dense specimen generated by a special algorithm which uses the real grain distribution of powder. The numerical model has been calibrated and validated through simulations of the real process of hot pressing of intermetallic NiAl material. The kinetics of compaction, sintering and cooling stage indicated by the evolution of density, shrinkage and densification rate have been studied. The comparison of numerical and experimental results has shown a good performance of the developed numerical model.     

YSZ陶瓷膜流延等静压复合成型新工艺研究

本文报道了ＹＳＺ陶瓷膜流延等静压复合成型的新工艺．研究了等静压对素坯膜和烧结膜材密度及显微结构的影响规律及电学性能的变化．指出对流延素坯膜进行等静压,工艺过程不复杂,但可使素坯的成型密度提高８％～１１％,同时烧结膜材的相对密度可提高５％～１０％     

Cold Isostatic‐Pressured Silver Nanowire Electrodes for Flexible Organic Solar Cells via Room‐Temperature Processes

Transparent conducting electrodes (TCEs) are considered to be an essential structural component of flexible organic solar cells (FOSCs). Silver nanowire (AgNW) electrodes are widely used as TCEs owing to their excellent electrical and optical properties. The fabrication of AgNW electrodes has faced challenges in terms of forming large uniform interconnected networks so that high conductivity and reproducibility can be achieved. In this study, a simple method for creating an intimate contact between AgNWs that uses cold isostatic pressing (CIP) is demonstrated. This method increases the conductivity of the AgNW electrodes, which enables the fabrication of high‐efficiency inverted FOSCs that have a power conversion efficiency of 8.75% on flexible polyethylene terephthalate with no short circuiting occurring as the CIP process minimizes the surface roughness of the AgNW electrode. This allows to achieve 100% manufacturing yield of FOSCs. Furthermore, these highly efficient FOSCs are proven to only be 2.4% less efficient even for an extreme bending radius of R ≈ 1.5 mm, compared with initial efficiency.     

热等静压烧结Nd-Fe-B永磁体

热等静压烧结通常用来促进合金致密化和细化组织。本文尝试对Nd32．54Dy0．5Fe65．36Al0．6B1.0预烧结体分别进行热等静压烧结和常规烧结，旨在研究热等静压烧结能否促进Nd-Fe-B合金的致密化和晶粒细化。首次发现；高温热等静压烧结时，预烧结样品内的部分富Nd液相外流，在样品内形成空洞，被高压Ar气填充，造成样品不能收缩，磁体的密度比常规烧结磁体的低，力学性能明显恶化；且液相外流引起晶粒转动，导致取向度降低，最终磁体的剩磁和磁能积降低。     

YSZ流延片的等静压工艺研究

氧化钇稳定氧化锆(YSZ)流延片广泛应用于生产陶瓷传感器,但是流延素坯结构疏松、密度较低,严重影响产品强度。研究了等静压工艺对YSZ流延素坯的影响,通过测试密度、抗弯强度和观察微观结构得出,温等静压工艺更适合YSZ流延片的处理,并找出了最佳工艺参数。