预浸料工艺制备氧化铝纤维增强氧化铝陶瓷基复合材料

氧化物/氧化物陶瓷基复合材料的增强体和基体均由氧化物构成,不存在氧化问题,是长寿命高可靠性构件的理想选材,可在1000~1300℃的高温环镜中可长期使用。本文借鉴树脂基复合材料单向纤维湿法预浸料制备工艺,通过配置氧化铝粉体料浆在缠绕式湿法预浸机上制备了单向氧化铝纤维预浸料,然后预浸料经铺层模压和高温热处理获得了氧化铝纤维增强氧化铝陶瓷基复合材料,同时对复合材料性能进行了表征。结果表明,氧化铝粉体料浆的固含量在50vol%,料浆溶剂中水和丙三醇的比例为3:1,纤维的走丝速度为6m/min,滚筒平行进度为0.5mm时可获得无缝隙,无纤维重叠、表面平整光滑的预浸料。通过预浸料铺层热压成型制备的复合材料拉伸强度高达208.2MPa,弯曲强度为386.7MPa。和料浆涂刷二维纤维布工艺相比,力学性能大幅度提高,且预浸料工艺具有易存储、操作简单、适于工业化生产等优势。     

汽车前地板后本体复合模压成形工艺

针对汽车前地板后本体在线复合模压成形工艺,探究采用螺杆机混合浸润挤出的LFT-D高温坯料与单向碳纤维预浸料增强片的多元复合模压过程,通过正交实验法,研究复合模压成形的主要工艺参数(入模料温、模压压力、合模速度和保压时间等)对成形缺陷的影响,结合力学性能实验进行筛选,确定出了优化后的成形工艺组合参数为:单向碳纤维预浸料增...     

单向C/C复合材料的液相法制备及其显微结构

以沥青、沥青加焦炭粉和树脂加焦炭粉3种预浸料制备纤维预浸体，模压成型制备初坯体，然后用沥青液相法制备了3种单向C／C复合材料试样，对这些试样的密度、孔隙率和显微结构进行了测试和观察。在热压成型初坯体内，收缩微裂纹沿纤维轴向与外界相通，可被再浸渍填充，而孔洞则大多与外界隔绝，不能被再浸渍填充。添加焦炭粉作填料有利于C／C复合材料中纤维体积含量的控制、减少封闭气孔的形成，提高材料的密度。但焦炭粉末将扰乱基体层状结构组织，甚至使其出现紊乱状态。     

树脂磨具的松散性成型料研究

普通树脂磨具多以酚醛树脂粉为结合剂、酚醛树脂液为润湿剂,成型料容易发粘。结块、松散性很差,尤其在炎热、多雨的夏季,往往难于刮料。近几年,在引进的全自动压机上,加料和刮料都是机械化自动操作,对树脂磨具成型料的松散性比人工操作提出了更高的要求,为此,我们用国产原料对树脂松散料进行了初步的探索。1导致树脂成型料不松散的原因和解决的途径1．1导致原因我们认为导致成型料不松散、容易结块的主要原因是酚醛树脂液中含有游离酚（其含量为20％左右）,游离酚能溶解一部分酚醛树脂粉,致使粘附在磨粒表面的干树脂粉发粘。此外…     

碳纤维复合材料HP-RTM模压成形装备

<正>本文对碳纤维复合材料HP-RTM模压成形工艺所需的装备进行介绍,详细阐述了碳纤维复合材料模压成形装备的剪裁机、预成形装备、模压成形装备和切割机等。HP-RTM模压成形工艺是复合材料生产中一种制造高纤维体积含量的大型复杂构型的成形方法,它是由普通的塑料制品模压成形演变而来的,是一种对热固性树脂和热塑性树脂都适用的碳纤维复合材料成形方法。模压成形基本过程是：在模腔（模腔需要预先制作成特定尺寸）中铺放按性能和结构要求设计的增强材料预成形体,然后将预制体放入液压机模腔内,在压力注入或外加真空辅助条件下,液态树脂在闭合模具里流动并排出气体,同时浸润干态纤维预成形体,加热固化,得到制品。     

SMC制品模压模具局部后打孔结构设计

基于纤维增强的树脂基复合材料模压成型工艺的特点,针对模压制品上安装孔要求强度高、飞边小、内壁光滑的特点,设计了一种模压模具合模后局部挤压成型孔的结构,不仅增强了孔周围的强度,而且减少制品孔周围的飞边,可避免后续制品孔位在成型后进行修边导致孔的位置精度下降的问题,提高了制品质量。     

复合材料间接挤压铸造生产的工艺可行性研究

在工业压铸机上用间接挤压浸渗预成型块生产铝合金基体复合材料铸件的可行性研究.研究结果表明,在工业压铸机上用间接挤压浸渗强化相预成型块的方法生产铝合金基复合材料是可行的、预成型块浸渗行为遵从挤压浸渗动力学、复合材料铸件的工艺品质取决于工艺参数的合理性.在优化工艺条件下,可以生产出没有浸渗缺陷、预成型块变形、纤维断裂、基体缩孔疏松、宏观偏析的复合材料铸件.     

超细晶粒WC—Co硬质合金的剪切模压成型工艺

采用剪切模压新工艺成型,通过真空烧结制备出了超细晶粒ＷＣ－Ｃｏ硬质合金。研究了不同成型剂的特性、成型剂的配比、加入量以及压制力对剪切模压成型的影响。研究结果表明,采用剪切模压成型工艺可获得很高的成型质量,从而制备出具有较好物理力学性能的超细ＷＣ－Ｃｏ硬质合金。     

抗静电预涂钢板的开发

PCM（预涂金属）的涂膜主要由有机树脂（绝缘体）组成，涂膜表面与其它材料（如模具、皮带输送机）摩擦时产生静电，灰尘会粘附在PCM表面。在面涂中加入适当的树脂和添加剂，能抑制与其它材料摩擦所产生的表面静电压，从而防止灰尘的粘附。基于这种想法，开发了抗静电预涂钢板，抑制静电所导致的灰尘粘附。当静电压产生和灰尘粘附时，PCM显示了显著效果。通过选择底涂和预处理，也得到了一种不含铬酸盐型的PCM。希望这种抗静电的PCM将来能广泛应用于各个领域。     

超细晶料WC—Co硬质合金的剪切模压成型工艺

采用剪切模压新工艺成型，通过真空烧结制备出了超细晶粒WC－Co硬质合金。研究了不同成型剂的特性、成型剂的配比、加入量以及压制力对剪切模压成型的影响。研究结果表明，采厅剪切模压成型工艺可获得很高的成型质量，从而制备出具有较好物理力学性能的超细WC—C。因质合金。     

Effect of bonding process on the properties of isotropic epoxy resin-bonded Nd-Fe-B magnets

Bonded NdFeB magnets were prepared by compression molding. The effect of preparation technology on their magnetic and mechanical properties was studied through the analysis of density, Br Hcj, (BH)max, bending strength, and compressive strength of the bonded magnets. The results showed that the magnetic properties decreased with increasing binder content, whereas the mechanical properties increased. Brand (BH)max increased with rising pressure, whereas Hcj decreased. For a fixed mass fraction of the binder, the optimal pressure was 620 MPa and the best thermosetting temperature was 160℃. These conditions made the bonded magnets have the optimal mechanical properties. Scanning electron microscopy (SEM) analyses of the fracture surfaces indicated that the epoxy resin bonded magnets exhibited brittle behavior.     

树脂基复合材料固化过程中的变形分析

高性能热固性树脂基复合材料的固化过程中基体材料从粘流态转变为固态,这是一个复杂的热、化学和力学性能急剧变化的过程。树脂基复合材料在固化过程中随着树脂基体的逐渐固化,材料的力学性能也会随之产生明显改变,并且力学性能的改变会进一步影响材料成形后的残余应力和变形。因此有效地预测构件在固化过程中的应力和变形趋势对优化成形工艺以期得到适合要求的复材结构具有重要的指导作用。本文主要采用了细观力学的分析方法对热固性树脂基复合材料固化过程中的热、力学性能变化进行分析。数值模拟分析结果表明,材料在降温前其应力、应变量趋于稳定,但材料在降温前并不是处于理想的无应力状态。     

Research on Properties of Carbon Fiber/Epoxy Resin Composite Material by Microwave Curing

Microwave irradiation was used to reduce the curing time of carbon fiber/epoxy resin composite material.The properties of carbon fiber/epoxy resin composite material under microwave curing were investigated by thermogravimetry(TG),dynamic mechanical analysis(DMA),impact strength test and scanning electron microscope(SEM).The results show that composite materials patch have high thermal stability after microwave curing.The initial degradation temperature is 330.9℃,the maximum thermal decomposition rate is at 368.1℃.When the layer of composite materials patchis 4 layers,the dynamic mechanical properties are the best after microwave curing.The initial storage modulus is 43.2 GPa,increased 28.3 GPa and 27.1 GPa than 3 layers and 5 layers,the glass transition temperature(Tg)is 67.48℃,increased about 12 ℃than 3 layers and 5 layers.Microwave curing can significantly improve the infiltration capacity of epoxy resin,enhance interfacial bonding,and increase the impact strength of composite patch.Under microwave curing,the impact strength of 3,4,5-layers composite material patches increases 35.9%,6.4% and 15.1%,respectively than heating curing.The SEM analysis of impact fracture surface shows that microwave curing can improve the interface of carbon fiber and epoxy resin.     

有机酯-微波复合硬化水玻璃砂强度及抗吸湿性研究

对比研究了普通一次微波硬化、有机酯硬化、有机酯-微波复合硬化三种水玻璃砂硬化工艺的性能.结果表明,与普通一次微波加热硬化相比,有机酯-微波加热复合硬化工艺可使砂型在微波加热阶段不带模具加热,当有机酯的加入量为水玻璃质量的1.5％时,恒湿瓶中4h存放强度较普通一次微波加热硬化提高了70％;较之于有机酯硬化工艺,有机酯-微波加热复合硬化工艺的水玻璃加入量少、硬化速度快、硬化强度高.进一步系统研究了其他工艺参数(微波加热功率和时间)对有机酯-微波加热复合硬化水玻璃砂型存放强度的影响,并通过扫描电镜观察分析了该工艺下的砂样粘结桥微观结构和硬化机理.     

纳米银对环氧树脂的增韧改性及其微波固化行为

在80℃双酚A型环氧树脂E-51中,通过还原原位构筑了超分散稳定纳米银(n-Ag);用冷冻蚀刻电镜、离心实验对其进行表征和分散稳定性评价;用间歇微波对分散系中n-Ag的微波吸收特性和环氧树脂的微波固化行为进行研究;通过拉伸试验和冲击试验考察n-Ag对环氧树脂的增韧改性行为。结果表明:银为30nm的粒状颗粒,大小均匀,有理想的分散稳定性;n-Ag对环氧树脂有显著地增韧作用,当其含量为2.0%～2.5%(质量分数)时,增韧改性效果最佳,复合材料的断裂伸长率可提高l10%～130%;原位合成n-Ag有良好的微波吸收特性,它的存在能明显减少环氧树脂的微波固化时间,当n-Ag含量超过2.5%时,微波固化时间可缩短38%;微波固化环氧树脂速度比传统加热固化速度快数倍,其抗拉伸强度和抗冲击强度也好于热固化,但拉伸断裂伸长率比热固化的小。     

Effect of gel time of 3D sand printing binder system on quality of sand mold/core

Two important factors affecting the performance of sand mold/core generated by 3D printing (3DP) are strength and dimensional accuracy,which are not only closely related to the reactivity of furan resin and the phase transition of silica sand,but also the curing agent system of furan resin.This paper studies the influence of gel time on the strength and dimensional accuracy of a 3DP sand mold/core,taking the furan resin system as an example and using a sand specimen generated by a 3DP inkjet molding machine.The experiment demonstrates that the gel time of 3 to 6 min for the sand mixture suits 3DP core-making most under the experimental condition.However,it should be noted that under the same resin condition,the strength of a no-bake sand mold/core is higher than that of a 3DP sand mold/core.The dimensional accuracy of the sand mold/core does not change significantly when the gel time is less than 15 min.Improving the activity of binder and developing ultra-strong acid with low corrosion shall be an effective way to improve the quality of the mold/core by 3D printing.     

Fiber Reinforced Polyester Resins Polymerized by Microwave Source

Polyester resin based composite materials are widely used in the manufacture of fiberglass boats. Production time of fiberglass laminate components could be strongly reduced by using an intense energy source as well as microwaves. In this work a polyester resin was used with 2% by weight of catalyst and reinforced with chopped or woven glass fabric. Pure resin and composite samples were cured by microwaves exposition for different radiation times. A three point bending test was performed on all the cured samples by using an universal testing machine and the resulting fracture surfaces were observed by means of scanning electron microscopy (SEM). The results of mechanical and microscopy analyses evidenced that microwave activation lowers curing time of the composite while good mechanical properties were retained. Microwaves exposition time is crucial for mechanical performance of the composite. It was evidenced that short exposition times suffice for resin activation while long exposure times cause fast cross linking and premature matrix fracture. Furthermore high-radiation times induce bubbles growth or defects nucleation within the sample, decreasing composite performance. On the basis of such results microwave curing activation of polyester resin based composites could be proposed as a valid alternative method for faster processing of laminated materials employed for large-scale applications.     

热固性塑料线圈架精密注射模设计

通过对某型需要大批量生产的热固性塑料线圈架零件进行结构和成型工艺分析,拟定了其精密注射成型生产方案;设计了一种便捷的导槽式垂直分型的模具结构,介绍了热固性塑料精密注射成型模具的结构及其特点。     

Research of warm compaction technology on nylon bonded Nd-Fe-B magnets

Warm compaction and room temperature compaction were applied to prepare bonded Nd-Fe-B magnets. The results indicated that the density of magnet was determined by the compaction pressure and warm compaction temperature, whereas, the thermosetting temperature could hardly affect the density of magnet. The mechanical properties of magnets were the best when the thermosetting temperature was 200 ℃. The Br, Hcb, and (BH)max of warm compaction magnet were higher than those of room compaction. When the warm compa...