Zn-Al合金对碳纤维浸渗性研究及复合层板制备

发布时间：2018-07-28 21:09

【摘要】：在过去三十年，人们一直在寻找一种集质轻，强度高，抗冲击，耐疲劳和耐腐蚀一体的材料，玻璃纤维/环氧树脂增强铝合金层板在一定程度上满足上述要求。然而这种复合材料存在着层间结合强度低，易发生层间剥离，同时环氧树脂耐高温性能差，易老化等缺点。因此选用金属连接剂来代替环氧树脂可以有效克服上面缺点。本文选用Zn-Al合金作为中间连接剂来代替传统的环氧树脂，利用热压法制备出了碳纤维增强5052铝基复合材料。首先研究了Zn-Al合金在半固态下对碳纤维布的浸渗性。研究了合金成分和热压温度这两个变量对半固态Zn-Al合金的浸渗性能的影响及渗透原理。然后选用浸渗性较好的Zn-Al合金作为连接剂，在最佳温度下热压制备碳纤维增强5052铝基复合材料，然后辅以超声波震动及保温处理得到最终的复合材料。采用电子万能试验机对复合材料进行了室温拉伸力学性能测试（纵向拉伸）；利用扫描电子显微镜（SEM）对复合材料层界面的微观结构进行了观察分析；同时结合能谱仪（EDS）进行了成分分析。实验结果表明：（1）Zn-8Al合金和Zn-27Al在固液比相同的半固态下表现出了对碳纤维不同的浸渗性能。Zn-8Al合金能很好浸渗到碳纤维内部而Zn-27Al不能浸渗碳纤维。（2）提高半固态下的热压温度，虽然液体含量增加，但是对碳纤维浸渗性并不表现出线性的相关性。（3）热压过程中半固态浆料的渗透性可以用半固态中的固相析出速率值（SFIR）进行评估，SFIR值跟相图中的固相线和液相线斜率成反比，同Cs-Cl值成反比。在热压渗透过程中，具有较低的SFIR半固态浆料表现出对碳纤维布较高的渗透性。（4）使用Zn-8Al合金作为中间连接剂，通过热压法制备碳纤维复合材料。碳纤维在连接剂中均匀弥散分布，纤维与连接剂结合良好，连接剂中无明显空洞，缩松等缺陷。(5) Zn-Al合金层与5052基体层之间发生了元素扩散，两者之间的界面是通过冶金结合的方式形成的界面。(6)通过测量复合材料的力学性能，发现碳纤维体积分数达到24.7%时，复合板的抗拉强度和弹性模量分别达到了200MPa和167GPa，跟基体5052相比，抗拉强度和弹性模量分别提高了32.4%和50%。上述结果表明Zn-Al合金在半固态下对碳纤维的浸渗主要取决于SFIR值的大小，SFIR越小，对碳纤维的浸渗性越好。这对选择浸渗性良好的中间连接剂有着指导意义。Zn-8Al作为中间连接剂可以充分发挥连接作用，制备的复合材料跟基体相比强度与弹性模量都有了明显提高。
[Abstract]:In the past 30 years, people have been looking for a lightweight, high strength, impact resistance, fatigue and corrosion resistant materials, glass fiber / epoxy reinforced aluminum alloy laminates to a certain extent meet the above requirements. However, the composites have the disadvantages of low interlaminar bonding strength, easy interlaminar peeling, poor high temperature resistance and easy aging of epoxy resin. Therefore, the use of metal bonding agent to replace epoxy resin can effectively overcome the above shortcomings. In this paper, carbon fiber reinforced 5052 aluminum matrix composites were prepared by using Zn-Al alloy as intermediate connector instead of traditional epoxy resin. The infiltration properties of carbon fiber sheets (CFRP) by Zn-Al alloy in semi-solid state were studied. The effect of alloy composition and hot pressing temperature on the infiltration properties of semisolid Zn-Al alloy and its permeation principle were studied. Then carbon fiber reinforced 5052 aluminum matrix composites were prepared by hot pressing at the best temperature, and then the final composite was obtained by ultrasonic vibration and heat preservation. The tensile mechanical properties at room temperature (longitudinal tension) were measured by electronic universal testing machine, and the microstructure of composite layer interface was observed and analyzed by scanning electron microscope (SEM). At the same time, the composition analysis was carried out with (EDS). The experimental results show that: (1) Zn-8Al alloy and Zn-27Al show different infiltration properties of carbon fiber under the same solid-liquid ratio. Zn-8Al alloy can infiltrate carbon fiber well, but Zn-27Al can not infiltrate carbon fiber. (2) the hot pressing temperature in semi-solid state is increased. Although the liquid content increased, However, there is no linear correlation to the infiltration of carbon fiber. (3) the permeability of semi-solid slurry during hot pressing can be evaluated by using the solid-state precipitation rate value (SFIR), which is inversely proportional to the slope of the solid and liquid lines in the phase diagram. Is inversely proportional to the Cs-Cl value. In the process of hot pressing infiltration, the semi-solid SFIR slurry exhibits high permeability to carbon fiber cloth. (4) carbon fiber composites are prepared by hot pressing method using Zn-8Al alloy as intermediate bonding agent. Carbon fiber distributes uniformly in the binder, the fiber binds well with the binder, there are no obvious voids and shrinkage in the bonding agent. (5) there is element diffusion between the Zn-Al alloy layer and the 5052 matrix layer. The interface between the two is formed by metallurgical bonding. (6) by measuring the mechanical properties of the composite, it is found that when the volume fraction of carbon fiber reaches 24.7, The tensile strength and elastic modulus of the composite plate are up to 200MPa and 167 GPA respectively. Compared with the matrix 5052, the tensile strength and elastic modulus of the composite plate are increased by 32. 4% and 50%, respectively. The results show that the infiltration of carbon fiber by Zn-Al alloy in semisolid depends on the smaller the SFIR value, the better the infiltration ability of carbon fiber is. It is of guiding significance to select the intermediate bonding agent with good infiltration. Zn-8Al as the intermediate bonding agent can give full play to the bonding effect, and the strength and elastic modulus of the prepared composites are obviously improved compared with the matrix.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB333

【参考文献】