沥青基碳纤维增强铝基复合材料组织及性能研究

发布时间：2018-03-18 10:38

  本文选题：Cf/Al复合材料　切入点：显微组织　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文通过挤压铸造法制备沥青基Cf/Al复合材料,利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、能谱仪(EDS)等仪器对复合材料和碳纤维的显微组织进行观察,对复合材料的热物理性能和力学性能进行了测试。分析了不同种类的沥青基碳纤维(K1100、P120和P100)以及不同的基体合金(1199、6063和5A06)对复合材料组织、热物理性能和力学性能的影响。碳纤维表征结果说明:碳纤维石墨化度越高、微晶尺寸越大、片层越完整、片层取向性越高,其轴向热导率越高。因此,沥青基碳纤维P100、P120和K1100相较于PAN基纤维具有更高的轴向热导率和弹性模量。复合材料界面结合良好,没有碳化物Al4C3生成;当Mg元素含量较低时,Mg元素以置换固溶体的形式存在于铝合金基体中;当Mg含量较低时,Mg元素以置换固溶体的形式存在于铝合金基体中;当基体合金中加入的Mg含量达到6.5wt.%时,界面生成大量的Al3Mg2。沥青基Cf/Al复合材料的纵向热导率测试值在284.7 W/m K至417.7 W/m K之间,横向热导率在38.2 W/m K至98.3 W/m K之间。其中P100/6063复合材料的纵向热导率高达390.7W/m K,与ROM模型吻合;而5A06为基体的复合材料在基体中固溶大量的Mg原子,使复合材料的热导率降低。以1199和6063为基体的复合材料热的纵向平均热膨胀系数在-1×10-6/K至1×10-6/K范围内,表现出低膨胀特性。而5A06基体的热膨胀系数较高,使复合材料的纵向热膨胀系数较高。温度和碳纤维的种类对复合材料的横向热膨胀系数影响较小,20~100℃范围内平均热膨胀系数在16×10-6/K至26×10-6/K之间,符合Kural-Min模型。复合材料的热循环实验结果表明:第一次循环过程出现开环,这主要与复合材料中的残余应力松弛有关;且由于基体合金的塑性变形作用,在循环过程中出现了明显的应变滞后环。以6063为基体的复合材料的弹性模量和抗弯强度较高,其中P120/6063复合材料的弹性模量和抗弯强度分别达到了496.4GPa和703MPa。断口分析表明:复合材料主要以纤维拔出方式失效,通过适当合金化能有效减少碳纤维的拔出数量和拔出长度。
[Abstract]:In this paper, asphalt matrix Cf/Al composites were prepared by squeeze casting. The microstructure of the composites and carbon fibers were observed by means of optical microscope, scanning electron microscope, transmission electron microscope and energy spectrometer. The thermo-physical properties and mechanical properties of the composites were tested. The microstructure of the composites was analyzed by using different kinds of asphalt-based carbon fibers K1100P120 and P100) and different matrix alloys (11996063 and 5A06). The results of carbon fiber characterization show that the higher the graphitization degree of carbon fiber is, the larger the crystallite size is, the more complete the lamellar is, and the higher the orientation of the lamellar is, the higher the axial thermal conductivity is. Compared with PAN fiber, P100 / P120 and K1100 have higher axial thermal conductivity and modulus of elasticity. The interface of the composites is well bonded and no carbides are formed by Al4C3. When the mg content is low, the mg element exists in the aluminum alloy matrix in the form of replacement solid solution, when the mg content is low, the mg element exists in the aluminum alloy matrix in the form of the replacement solid solution, and when the mg content in the matrix alloy reaches 6.5 wt.%, A large amount of Al _ 3mg _ 2 was generated at the interface. The longitudinal thermal conductivity of the Cf/Al composites was between 284.7 W / m K and 417.7 W / m K, and the transverse thermal conductivity was between 38.2 W / m K and 98.3 W / m K. The longitudinal thermal conductivity of the P100 / 6063 composite was 390.7 W / m K, which was consistent with the ROM model. However, when 5A06 matrix composites dissolve a lot of mg atoms in the matrix, the thermal conductivity of the composites decreases. The longitudinal average thermal expansion coefficient of the composites with 1199 and 6063 matrix is from 1 脳 10 ~ (-6) / K to 1 脳 10 ~ (-6) / K, and the average thermal expansion coefficient of the composites is in the range of 1 脳 10 ~ (-6) / K to 1 脳 10 ~ (-6) / K. The thermal expansion coefficient of 5A06 matrix is higher than that of 5A06 matrix. The longitudinal thermal expansion coefficient of the composite is higher. The average thermal expansion coefficient of the composite is between 16 脳 10 ~ (-6) / K and 26 脳 10 ~ (-6) / K in the range of 20 鈩，

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