铝镁层合板半固态金属层界面的形成及与碳纤维的复合机制

The carbon fiber reinforced aluminum alloy laminates of metallurgically bonded are superior to those of epoxyed in thermal stability, heat and electric conductivity, thermal shock resistance and moisture-proof, while magnesium laminates possess the superiority of lightweight. At the present, however, it is still difficult to get a good metallurgical bonding between the matal plates and carbon fibres. This proposal proposes to add the solder of eutectic alloys with low melt points between the plates. The eutectic alloys would melt and infiltrate the fibers at low temperatures. With the add of viberation, the reactivity between the metal melt and the metal plates or other solid metals added would be enhanced, which results in the composition change of the melt and promotes to form a semisolid slurry with good fluidity. The slurry washs and wets the fiber under the vibration. Cooled after hot-rolling or hot-pressing, a semisolid structure rather than a brittle eutectic structure is formed between the the plates. This proposal chooses Al alloy and Magnesium alloy as the metal plates, to study the transformtion process of the solder from eutictic melt to semisolid slurry and its influence on the wettability of the metal to carbon fibers, to establish the relationship between the mechanical properties (the interlaminar bonding strength and interlaminar fracture toughness, stregth, stiffness and fatigue resistane of the laminates) and processing conditions (hot-pressing tempreture, load, time, and frequency and energyrate of vibration), and to provide the theoretical basis and the experimental data for development of metallurgically bonded carbon fiber reinforced aluminum and magnesium laminates.

冶金结合的碳纤维增强铝合金层合板，在热稳定性、热电传导性、抗热震和防潮性能等方面，优越于环氧树脂粘接的纤维增强铝合金层合板，而镁合金层合板则更具轻质优势。本项目针对目前难以实现碳纤维与组元板间良好冶金结合的问题，提出在板层间添入低熔点共晶合金，在尽可能低的温度下熔化并浸润碳纤维；借助振动搅拌，促进共晶液与组元板合金或其它添加金属的反应，成为液-固两相并存、流动性良好的半固态金属浆料，并增强浆料对碳纤维的冲刷，实现二者良好润湿。热轧或热压冷却后，层界面形成半固态凝固组织而非脆性的共晶组织。本项目选铝合金或镁合金作组元板，研究各类熔合剂在层界面向半固态的转变过程及其对碳纤维润湿性的影响规律，建立层界面结合强度和层间断裂韧性、层合板的强度、刚度、疲劳性能与板层结构、熔合剂组成及热压温度、压力、保温时间、振动频率和能率之间的关系，为开发冶金结合的碳纤维增强铝镁层合板提供理论依据及实验数据。

冶金结合的碳纤维增强镁铝层合板，在热稳定性、热电传导性、抗热震和防潮性能等方面，优越于环氧树脂粘接的纤维增强镁铝层合板。但目前难以实现碳纤维与组元板间良好冶金结合。.本项目提出在板层间添入低熔点共晶合金，研究了不同熔合剂对纤维的浸润情况。结果表明通过热压工艺，三元共晶合金Mg-Zn-Al及二元共晶合金Zn-Al能充分浸润碳纤维。热压过程中浆料对纤维的浸渗性可以用固相析出速率值来评估（SFIR）。SFIR值越低，浸渗性能越好。.选用AZ31B镁合金层板与Mg-Zn-Al制备出高界面结合强度和高抗拉强度的纤维增强镁合金层合板。碳纤维与共晶熔合剂结合方式为机械结合，而熔合剂与镁合金层板通过扩散反应形成结合强度较高的冶金结合。选用5052铝合金层板与Zn-Al合金制备出冶金结合的碳纤维增强铝基层合板，层合板抗拉强度与5052基体相比提高了32.4%。.通过半固态搅拌铸造和慢速热挤压方法制备了SiCp增强Mg-Zn-Ca复合材料。结果表明挤压后的SiCp/Mg-Zn-Ca复合材料呈现出二重晶粒结构。复合材料的力学性能优于其它方法制备的颗粒增强镁基复合材料。本项目的研究成果为后续制备冶金结合的纤维增强金属层合板提供了实验依据，对纤维增强层合板的工业应用具有重要意义。