石墨烯增强铝基复合材料组织及性能研究

发布时间：2018-03-25 20:35

本文选题：旋转摩擦挤压技术　切入点：石墨烯　出处：《南昌航空大学》2017年硕士论文

【摘要】：本文分别以1060工业纯铝和7075铝合金为基材,多层氧化石墨烯(Graphene Oxide)为增强相,采用旋转摩擦挤压(Rotational Friction Extrusion,RFE)技术制备了石墨烯含量分别为0.25wt%、0.6wt%和1wt%的石墨烯增强铝基复合材料。在确定了制备的最佳工艺参数的基础上,研究了石墨烯含量对复合材料成形和组织的影响规律,并通过对复合材料进行XRD、SEM和EMPA试验分析了其物相组成及石墨烯分布的均匀性,同时测定了复合材料的显微硬度、抗拉强度、延伸率和电导率,对拉伸断口进行了SEM观察,最后对石墨烯增强铝基复合材料的强化机制进行了探讨。所得主要结论如下:采用旋转摩擦挤压技术可制备出外观成形良好的石墨烯增强铝基复合材料。当旋转速度为555rpm,挤压速度为0.36mm/s时,制备的石墨烯增强1060Al复合材料棒料宏观形貌良好,长度可达约140mm;当旋转速度为315rpm,挤压速度为0.28mm/s时,制备的石墨烯增强7075Al复合材料棒料的长度达到约150mm且宏观形貌较好。石墨烯的含量对复合材料的成形有很大影响,并具有细化晶粒的作用且分布较为均匀。当石墨烯含量为0.25wt%时,复合材料成形较好无明显缺陷,但随着石墨烯含量的增加,复合材料表面有严重缺陷并出现开裂。通过显微观察和XRD、SEM和EMPA试验,发现复合材料的组织为均匀细小的等轴晶,石墨烯在复合材料中分布较为均匀,且未与Al基体发生化学反应,未生成Al4C3等脆性界面产物。复合材料的力学和导电性能在石墨烯加入后显著提高。随着石墨烯含量的增加,复合材料的显微硬度、抗拉强度和电导率均随之提高。1wt%1060Al复合材料的硬度为43.3HV,较纯铝提高了72.5%;1wt%7075Al复合材料的硬度为132.3HV,是经过RFE加工的7075Al基材的1.26倍。0.6wt%1060Al复合材料的抗拉强度达到113.4MPa,是纯铝的1.37倍,断口呈宏观脆性断裂;0.6wt%7075Al复合材料的抗拉强度为474.4MPa,比经过RFE加工的7075Al基材提高了22.3%,断口呈微观韧性断裂。0.25wt%1060Al复合材料的电导率比纯铝提高了3.6%,其IACS值约为80%,0.25wt%7075Al复合材料的电导率IACS值为40.3%,较经过RFE加工的7075Al基材提高了5.2%。
[Abstract]:In this paper, 1060 industrial pure aluminum and 7075 aluminum alloy were used as substrates and graphene oxide was used as reinforcing phase. Graphene reinforced aluminum matrix composites with 0.25wt% graphene content and 1wt% graphene content were prepared by rotating friction extrusion Friction extension technique. The effect of graphene content on the forming and microstructure of composites was studied. The phase composition and the homogeneity of graphene distribution were analyzed by XRD-SEM and EMPA tests. The microhardness of the composites was also measured. Tensile strength, elongation and conductivity were observed by SEM. Finally, the strengthening mechanism of graphene reinforced aluminum matrix composites is discussed. The main conclusions are as follows: the graphene reinforced aluminum matrix composites with good appearance can be prepared by rotating friction extrusion. When the speed is 555rpm, the extrusion speed is 0.36mm/s, The graphene reinforced 1060Al composites have good macroscopic morphology and the length is about 140 mm. When the rotation speed is 315rpm and the extrusion speed is 0.28mm/s, The length of graphene reinforced 7075Al composites is about 150mm and the morphology is good. The content of graphene has a great influence on the forming of the composites. When the content of graphene is 0.25 wt%, the composite has no obvious defects, but with the increase of graphene content, The microstructure of the composite was found to be uniform and small equiaxed crystal, and the graphene was distributed uniformly in the composite by microscopical observation and XRDX SEM and EMPA tests, which showed that there were serious defects and cracks on the surface of the composite. There was no chemical reaction with Al matrix and no brittle interface products such as Al4C3. The mechanical and conductive properties of the composites increased significantly after the addition of graphene, and the microhardness of the composites increased with the increase of graphene content. The tensile strength and electrical conductivity of the composites increased with the increase of 43.3HVV, and the hardness of the composites was 132.3HV. the hardness of the composites was 132.3HV. the tensile strength of the composites was 1.26 times of that of the 7075Al substrates processed by RFE, and the tensile strength of the composites was 113.4MPa. it was 1.37 times that of the pure aluminum, and the tensile strength of the composites was 1.26 times of that of the 7075Al substrates processed by RFE and 1.37 times that of the pure aluminum. The tensile strength of the composite with macroscopic brittle fracture of 0.6wtp75Al is 474.4MPa, which is 22.3mm higher than that of the 7075Al substrate fabricated by RFE. The electrical conductivity of the 60Al composite with micro-toughness fracture of 0.25wt / 60Al is 3.6cm higher than that of pure aluminum, and its IACS value is about 800.25wtp75Al. The conductivity IACS value of 7075Al is 40.3, which is 5.2% higher than that of 7075Al substrate processed by RFE.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB333

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