熔合剂改性对碳纤维增强5052铝合金层合板力学性能的影响

发布时间：2018-05-03 06:24

本文选题：碳纤维 + 熔合剂　；参考：《太原理工大学》2017年硕士论文

【摘要】：碳纤维增强铝合金层合板具有低密度、高比强度、优越的耐腐蚀性能及尺寸稳定性,在航空航天领域具有广阔应用前景,但因界面润湿性差或界面反应等问题,实现铝合金与碳纤维的直接高质量界面结合较困难,限制了其广泛应用。在Al基体与碳纤维间使用合金熔合剂解决界面结合问题是一种有效手段。Zn-8Al合金有较好的塑韧性及强度,能在较低温度下良好浸润碳纤维且与Al板形成有效界面结合。通过对熔合剂Zn-8Al合金化,可进一步改善其自身及层合板整体的力学性能。为此,本文选取添加Cu、Si合金元素及采用均匀化退火工艺对熔合剂进行改性,探究不同含量Cu元素、不同含量Si元素、不同时间均匀化退火对层合板力学性能的影响。本文采用磁悬浮熔炼炉进行Zn-8Al系熔合剂合金熔炼,通过铺层热压法制备层合板,以实现熔合剂与5052Al板的高质量界面结合。使用箱式电阻炉进行退火处理。使用光学显微镜(OM)和扫描电镜(SEM)观察微观组织形貌,使用能谱分析仪(EDS)和X射线衍射仪(XRD)对组织成分及物相进行分析,通过电子万能试验机及纳米压痕仪对层合板的拉伸力学性能及微区力学性能进行测试。研究结果表明:(1)Zn-8Al-XCu熔合剂组织由η(Zn)、α(Al)、ε(CuAl_2)三种物相组成,从η(Zn)、α(Al)两相中析出的树枝状ε(CuAl_2)组织与层合板力学性能紧密相关。随着Cu含量从1%增大到5%,ε(Cu Al_2)逐渐增多并缠绕成网状,层合板的抗拉强度逐渐提高,伸长率先增大后减小。少量的ε(CuAl_2)相能有效改善合金塑性,含量过高会降低层合板塑性。Cu含量3%时,层合板综合力学性能最佳,抗拉强度和伸长率分别达到315 MPa和1.31%。4%、5%Cu含量的熔合剂制备的层合板弹性模量明显变大,达到碳纤维增强的目的。(2)Si在Zn-8Al-XSi熔合剂中以单质硅的形式存在,Zn-8Al-XSi熔合剂组织中只有η(Zn)、α(Al)、Si三种物相。硬脆相Si直接影响层合板力学性能,Si含量从0.5%增大到2.5%过程中,层合板伸长率逐渐减小,抗拉强度先增大后减小。1%Si含量的层合板性能最佳,抗拉强度、伸长率分别达到365 MPa和0.78%。Zn-8Al-XSi熔合剂中Si含量应控制在1%以下。(3)随着均匀化退火时间增大,Zn-8Al-1Si熔合剂组织晶间偏析减缓,晶粒成分和尺寸均匀化程度提高。层合板抗拉强度降低,伸长率增大。晶粒成分均匀化是层合板塑性增强的决定因素。
[Abstract]:Carbon fiber reinforced aluminum alloy laminates have low density, high specific strength, excellent corrosion resistance and dimensional stability, and have a broad application prospect in the field of aerospace, but due to poor interface wettability or interface reaction, etc. It is difficult to realize the direct high quality interface between aluminum alloy and carbon fiber, which limits its wide application. It is an effective method to solve the interface bonding problem between Al matrix and carbon fiber by using alloy fusion agent. Zn-8Al alloy has better plastic toughness and strength, it can infiltrate carbon fiber well at lower temperature and form effective interface bonding with Al plate. By alloying the fusion agent Zn-8Al, the mechanical properties of the laminated plate and itself can be further improved. In this paper, the effect of Cu content, Si content and time homogenization annealing on the mechanical properties of laminates was investigated by adding Cu-Si alloy elements and homogenizing annealing process. In this paper, the magnetic suspension melting furnace is used to melt the Zn-8Al fusion alloy, and the laminated plate is prepared by hot pressing, so as to realize the high quality interface bonding between the fusion agent and the 5052Al plate. Use box resistance furnace for annealing. The microstructure was observed by means of optical microscope (Om) and scanning electron microscope (SEM). The composition and phase of the tissue were analyzed by energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The tensile and micromechanical properties of laminates were measured by electronic universal testing machine and nano-indentation instrument. The results show that the structure of Zn-8Al-XCu fusion agent consists of three kinds of phases: 畏 ~ (ZN), 伪 ~ (+) (Al ~ (2), 蔚 _ (CuAl2). The dendritic 蔚 -CuAl2) precipitated from 畏 _ (Zn), 伪 ~ (2) phase are closely related to the mechanical properties of the laminated laminates, and the results show that the structure of Zn-8Al-XCu melt is closely related to the mechanical properties of the laminated plywood. With the increase of Cu content from 1% to 5%, 蔚 CuAl2) gradually increased and wound into a network, and the tensile strength of laminated plates increased gradually, and the elongation increased first and then decreased. A small amount of 蔚 CuAl2) phase can effectively improve the plasticity of the alloy. When the content is too high, the plastic properties of the laminated plate can be reduced. When the content of Cu is 3, the comprehensive mechanical properties of the laminated plate are the best. The tensile strength and elongation reached 315 MPa and 1.31%, respectively, and the elastic modulus of the laminates prepared by the fusion agent with Cu content increased obviously. To achieve the purpose of carbon fiber reinforcement, there are only three phases in the microstructure of Zn-8Al-XSi fluxes in the form of simple silicon in the form of Zn-8Al-XSi fluxes. There are only three phases in the microstructure of Zn-8Al-XSi fluxes. In the process of increasing the mechanical properties and Si content of laminates from 0.5% to 2.5%, the elongation of laminates decreases gradually, and the tensile strength increases first and then decreases. The tensile strength of laminated plates is the best and the tensile strength is the best. The intergranular segregation of Zn-8Al-1Si fluxes decreases with the increase of homogenization annealing time, and the homogenization of grain composition and size increases with the increase of annealing time. The tensile strength of laminated plate decreases and the elongation increases. The homogenization of grain composition is the decisive factor of plastic strengthening of laminated plates.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB333

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