SiCp对石墨烯-铝基复合材料性能的影响研究

通过高能球磨混料和真空热压方法制备了铝基复合材料样品。采用金相显微镜、扫描电镜和硬度测试等实验手段研究了SiC纳米颗粒对石墨烯-铝基复合材料均匀性、致密度、微观结构和硬度的影响。结果表明,SiC纳米颗粒的加入改善了石墨烯的团聚情况,提升了铝基复合材料的致密度,也使铝基复合材料的硬度得到明显增强;但随着石墨烯含量的增加,铝基复合材料均匀性、致密度仍呈现下降趋势。     

原位合成TiC/Al基复合材料研究

用LEYBOLD-HERAEUS水冷铜坩埚真空电弧炉原位合成制备了TiC／Al基复合材料．X射线衍射谱表明，按20％TiC-Al配比，制得TiC-Al基复合材料中，TiC是唯一的增强相：在高温显微镜中在400℃、100MPa、真空度为0．00013Pa，压缩5h条件下，材料表现出良好的高温持久强度，TiC相未发生偏聚、差热分析(DTA)，显示该材料在900℃以下。TiC无相变发生．进一步证明原位。TiC／Al复合材料具有良好的热稳定性．光学金相、SEM和TEM观察显示，TiC颗粒与基体界面干净，压缩后位错呈半环状，绕TiC相堆积，说明即使在400℃高温下，加载后位错只能以Orowan机制绕过TiC相。     

玻璃纤维增强环氧树脂单向复合材料力学性能分析

采用连续玻璃纤维与环氧树脂相复合,通过金属模压成型工艺,制备出单向玻璃纤维／环氧树脂复合材料。通过三点弯曲实验论证单向纤维对树脂基体的增强作用,从而研究不同纤维含量下复合材料的弹性模量、纵向拉伸强度、纵向压缩强度的变化趋势。结果表明：随着纤维含量的增加,复合材料的力学性能均增强,当纤维体积含量为50％时,其各项性能均较好,弹性模量为40GPa,纵向拉伸强度为1200MPa,纵向压缩模量为700MPa。此外,对复合材料的其他常用力学性能参数进行检测。     

热循环对Ti（C,N）p／Ni材料组织和力学性能的影响

为探索铜合金热挤压用耐热模具材料的生产工艺，将粉末用机械球磨法混合，在石墨模中于1300－1350℃时热压制备了Ti(C,P)p/Ni复合材料试样，并对试样进行了热循环处理，在900℃加热1h，再在室温下冷却1 h为1个热循环周期，测定了试样的抗弯强度，硬度和内应力，并结合复合材料试样的显微组织变化情况分析了热循环处理对复合材料的抗弯强度，硬度和内应力的影响。结果表明，热循环次数从0次增加200次，复合材料的抗弯强度从2．38GPa降低到1．78GPa，内应力由循环50次时的20MPa减小到热循环100次时的5MPa;HRA硬度平均值为80．85，硬度基本保持不变。这表明，用石墨模具热压法制备耐热金属陶瓷颗粒复合材料是可地的，为耐热模具材料的工业生产提供了参考。     

碳纳米管增强铝基复合材料制备及性能研究

采用真空热压烧结法制备碳纳米管与 SiO2多相增强铝基复合材料,测量复合材料的体积密度,根据其理论密度计算其致密度;再对制得的复合材料进行硬度、抗压强度、抗剪强度等力学性能测试,并观察样品的剪切断口微观形貌,研究 CNTs 对复合材料力学性能的影响。低含量的碳纳米管由于其在铝基体中的分散性及弥散度较好,作为第二相增强相,所制备的铝基复合材料的致密度、硬度、抗压强度与剪切强度均优于高含量碳纳米管增强铝基复合材料。 CNTs 的含量、以及其在铝基体中的弥散度是影响铝基复合材料力学性能的关键因素。     

苎麻纤维／聚丙烯混纺混织增强复合材料的制备与性能研究

本文将改性的苎麻与树脂混纺或混织的织物在热压机上压制成苎麻纤维与树脂的复合板材。研究了织物组织结构、PP纱线在织物纬向上的含量等对苎麻／PP增强复合材料拉伸性能的影响。结果显示,对于混织预制体,当层数为5层,模压温度为175℃,模压压力为10MPa,苎麻／PP为1：1时,板材的拉伸性能最优,拉伸强度是83．03MPa;并且,由于斜纹组织的纱线伸直状态最好,所以其复合材料的机械性能优于缎纹组织和平纹组织复合材料。对于混纺预制体,模压温度为170℃,压力为12．5MPa,模压时间为20min,苎麻纤维体积分数为50％时,复合材料的拉伸性能最优,对于不同组织的织物,缎纹组织的复合材料的拉伸性能最好。     

纳米金属粒子/有机物复合材料组织结构的探讨

采用高能球磨法制备了纳米金属粒子/有机物复合材料,运用扫描电镜(SEM)、透射电镜(TEM) 和X射线衍射仪对复合材料的微观形貌特征和结构进行了分析研究,并探讨了球磨时间对复合材料微观形貌特征的影响.研究结果表明,经过超声振动后复合颗粒分布较均匀,100 h球磨后锌粒的粒径大约为100 nm左右,呈层片状分布,聚氯乙烯与锌复合后,均匀地包覆在锌粒的表面.球磨50 h、80 h、100 h和120 h铜粒的粒径分别为300 nm、140 nm、70 nm和30 nm左右,近似圆球状,石蜡可以完全包覆纳米铜粒子.     

石墨烯镀铜对铝基复合材料结构与性能的影响

采用球磨和真空热压方法制备石墨烯增强的铝基复合材料,研究石墨烯含量及其镀铜前后对复合材料微观结构、力学性能和磨损性能的影响。结果表明:石墨烯主要分布在基体合金晶界处,其质量分数增加到1%时,团聚严重,力学性能急剧降低,硬度和抗拉强度均有所降低;石墨烯镀铜后改善基体与增强相间的界面结合,使复合材料的硬度、抗拉强度和耐磨性较镀铜前均有一定程度提高。     

纳米铜基温敏复合材料的制备及其性能研究

采用高能球磨法制备了纳米铜基温敏复合材料.通过PHILIPS EM430型高分辨透射电镜(TEM)观察复合材料形貌,比较及确定了复合材料的粒径,进而采用热压成型工艺,将复合材料装入自制铜管(直径5 mm,长度20 mm,一端封闭),用温控光学测微装置测试其热敏性,着重探讨了球磨时间对复合材料微观形貌特征和热敏性的影响.研究结果表明,不同的球磨时间使复合材料粒径和形状发生变化,球磨时间对复合材料的热敏性影响显著,复合材料的热敏性随球磨时间延长而逐步提高.     

原位内生颗粒增强铝基复合材料研究进展

综述了原位内生颗粒增强铝基复合材料的研究现状,从增强相选择材料制备技术、界面表征、机械性能、反应机理等各个领域,详尽阐述了原位内生颗粒增强铝基复合材料的特点,并指出今后研究方向。     

ZrB2基层状复合材料力学性能与应力影响分析

通过层压复合技术制备出Mo/ZrB2层状复合材料,该复合材料的抗弯强度达到471 MPa,同时具有高的断裂韧性7.64 MPa·m1/2.研究发现材料内部的残余应力引起裂纹扩展阻力增大,裂纹发生偏转,材料因此得到强韧化.采用非均匀应变模型分析层状复合材料的内部残余应力,结果表明:基体层受拉应力,最大为64 MPa,界面层受压应力,最大为320 MPa,同时在层间存在剪切应力,最大为1.149MPa.基体层和界面层的厚度比对材料内部应力分布影响较大.     

Investigation on Mechanical Properties and Microstructure of Hydroxyapatite-SiCw Composite Bioceramics

Hydroxyapatite-SiCw composite micropowder was synthesized using in-situ composite method, and hydroxyapatite- SiCw composite bioceramics with different content of SiCw were produced by hot pressing sintering method. The microstructures of the materials were analyzed by SEM, and the relative density, bending strength and fracture toughness of the materials were tested. The results show that the mechanical properties of composite material are best when the whisker content is 20- 23.7% . The mechanical properties of the material are the best when the tensile stress acted on the composite material is parallel with the hot pressing plane, and they are the worst when the tensile stress acted on the composite material is normal to the hot pressing plane.     

Investigation on Mechanical Properties and Microstructure of Hydroxyapatite-SiC_w Composite Bioceramics

1Introduction Hydroxyapatitehasbecomeoneofthemostimportant artificialbonetransplantmaterialsbecauseofitsexcellent biocompatibility,osteophonyandhavingnoside effectto humanbody.Unfortunatelythemechanicalpropertiesof synthesizedhydroxyapatitearepoor,especia…     

包覆工艺制备C—SiC—B4C—TiB2复合材料的组织与性能

以鳞片石墨,B4C,SiC,TiO2为原料,利用包覆工艺在不同热压温度下制备了W（C）=50％的C—SiC—B4C—TiB2复合材料,并详细研究了热压温度对复合材料显微组织和性能的影响规律．结果表明,当热压温度高于1850℃时,复合材料由C,SiC,B4C和TiB2这四相组成;复合材料的体积密度、抗折强度和断裂韧性均随着热压温度的升高而增加．2000oC热压时,复合材料的体积密度、气孔率、抗折强度和断裂韧性分别达到2．41g／cm^3,3．42％,176MPa和6．1MPa·m^1/2;热压温度升高,复合材料的碳相和陶瓷相逐渐致密,碳相最终形成了在陶瓷基体上镶嵌的直径为40μm橄榄球状和条状这两种形貌．碳／陶瓷相的弱界面分层诱导韧化和第二相TiB2与陶瓷基体之间热膨胀系数不匹配所致的残余应力使变形过程中微裂纹的扩展路径发展变化,使复合材料的韧性提高．     

Physical and Mechanical Properties of PP Composites based on Different Types of Lignocellulosic Fillers

The presents preparation and characterization of different types of lignocellulosic fillers (pine wood sawdust/ walnut shell flour/ black rice husk powder) reinforced polypropylene composites were presented. The effect of MAPP as coupling agent (4wt%) on the physical and mechanical properties was also investigated. Polypropylene composites were prepared at different rates of filler/matrix (wt%) by using extrusion (for melt blending) and hot compression molding process. Maximum values of tensile and flexural strength were obtained as 26.1 and 43.4 MPa, respectively, whereas the elongation at break value was 4.11% at 10% pine wood sawdust reinforced PP. Tensile and flexural modulus of composites reached the maximum values as 3855 and 3633 MPa with the composite of 30% walnut shell flour reinforced PP. Characterization of composites was carried out by using tensile test, flexural test, FT-IR, and SEM.     

Preparation and mechanical properties of β-SiC nanoparticle reinforced aluminum matrix composite by a multi-step powder metallurgy process

β-SiC nanoparticle reinforced A1 matrix （nano-SiCp/A1） composite was prepared by a multi- step powder metallurgy strategy including presureless sintering, hot compacting process and hot extrusion. The microstructures of the as-prepared composites were observed by scanning electronic microscopy （SEM）, and the mechanical properties were characterized by tensile strength measurement and Brinell hardness test. The experimental results revealed that the tensile strength of the composite with the addition of 5wt%/3-SIC nanoprtieles could be increased to 215 MPa, increasing by 110% compared with pure A1 matrix. Comparative experiments reflected that theβ-SIC nanoprticles showed significant reinforcement effect than traditional a-SiC micro-sized particles. The preparation process and sintering procedure were investigated to develop a cost effective preparation strategy to fabricate nano-SiCp/A1 composite.     

预烧结对低压烧结WC-Co硬质合金组织和性能的影响

采用原位还原碳化反应制备超细WC-10%Co,在1250、1300、1350、1380℃进行预烧结处理,得到的预烧结块体在1450℃、5 MPa氩气条件下进行低压二次烧结;分析对比了预烧结块体和二次烧结块体的显微组织,并对二次烧结合金进行了性能测试.结果表明:不同温度预烧结块体经低压二次烧结后,可有效抑制晶粒异常长大现象,二次烧结后合金具有高的断裂韧性,最高值达16.1MPa·m-1/2.在1 350、1 380℃下预烧结块体经低压二次烧结后均具有均匀的合金组织,其中经过1380℃预烧结块体横向断裂强度为3260 MPa.     

纳米复合材料超声波焊接制备下剪切强度及组织研究

采用超声波焊接方法制备碳纳米管增强铝基复合材料,研究试件表面处理状态、焊接时间和焊接压力等工艺参数对焊接接头剪切强度的影响规律。试验结果表明:碳纳米管的加入具有较好的增强效果,提高了复合材料的力学性能;试件表面加乙醇处理、焊接时间120 ms及焊接压力17.5 MPa时,复合材料的接头剪切强度最高为11.12 MPa,相比基体材料提高28.6%;通过金相观察、扫描电镜(SEM)分析,发现碳纳米管很好地嵌入到了铝合金基体中,起到增强效果。     

短切芳纶纤维增强水泥砂浆准静态下力学性能研究

采用二步法制备不同纤维掺量的短切芳纶纤维增强水泥砂浆试样,研究添加剂羧甲基纤维素钠(CMC)和硅微粉对复合材料力学性能的影响.结果表明:羧甲基纤维素钠能够有效地促进纤维在水中的分散,进而促进其在水泥砂浆中的分散;掺加一定量的硅微粉能够进一步提高试样的压缩强度.当纤维体积分数为5％时,试样的力学性能最好,弯曲强度从2.6 MPa提高到了8.3 MPa,压缩强度也从29.5 MPa提高到了54.3 MPa.     

High-content graphene nanoplatelet reinforced aluminum composites produced by ball milling and hot extrusion

Due to the high specific surface area of graphene, the effective incorporation of high-content graphene in metals is challenging.Here, aluminum composites with graphene nanoplatelet(GNP) content up to 5.0 vol% were prepared by spark plasma sintering(SPS) of blended powders with various ball milling regimes and subsequent hot extrusion. The effects of GNP distribution state on the properties of GNP/Al composite were investigated. 5.0 vol% GNPs were uniformly dispersed in aluminum matrix by high-speed ball milling(HSBM) process, but with damage GNPs due to the too high energy input. By contrast, the wellstructured and dispersed GNPs in aluminum powders were obtained via shift-speed ball milling(SSBM). The clear GNP-Al interface in extruded SSBM composite was attributed to well-structured GNPs. As a result, the yield strength(YS) and ultimate tensile strength(UTS) of composite produced by SSBM reached 279 and 303 MPa, which are 166% and 116% higher than those of monolithic Al. This demonstrated that it may be promising to introduce high-content GNPs with tailorable interface in Al alloys via modified ball milling technique and hot extrusion.