Preparation, Mechanical Properties And Damping Capacities Of Mg/Al And Mg/Viscoelastic Materials Laminates

Magnesium and its alloys not only have the advantages of low density, high specific strength and strong electromagnetic shielding ability, but also are one of the metal structural materials with good damping capacity. So they show great potential in the application of lightweight and vibration/noise control. However, the low strength and poor corrosion resistance limit the wider use in actual production of magnesium. In order to obtain materials with excellent comprehensive performance, composite technology is an effective way to develop new materials, which can combine the characteristics and cover the shortage of different materials. Therefore, this paper regarded magnesium as the matrix. Through two different compositing method of “metal to metal” and “metal to non-metal”, Al/Mg/Al sandwich sheets and Mg/glass fiber reinforced epoxy resin laminates were fabricated respectively. Their mechanical properties, damping capacities and vibration performance were mainly studied so that a basis is laid for the further application of magnesium matrix laminates.The Al/Mg/Al sandwich sheets were fabricated by Al sheets and Mg sheets with different thickness through hot rolling. According to the thickness of Al and Mg in the sandwich sheets, Al rolling sheets and Mg rolling sheets were also fabricated. The interface of Al/Mg/Al is straight and there are no holes and microcracks existing in the interface, so the bonding results are good. The relative contents of Al and Mg have an effect on the mechanical properties of Al/Mg/Al sheets. And the damping capacities of Al/Mg/Al at room temperature, which is between the Mg and Al, is mainly affected by Mg layer and keep the high damping capacity of Mg layer. However, the Al layer has a greater influence on the damping capacities of Al/Mg/Al at high temperature. Annealing at 250℃ for 2 hours is confirmed to be the best annealing process for Al/Mg/Al sheets, which can promote the diffusion of atoms without producing the harmful intermetallic compound Mg2Al3. The yield strength and ultimate strength decreases and the elongation increases after annealing. In addition, the annealing process has a great impact on the damping capacities at room temperature of Al/Mg/Al sheets. The damping capacities decrease when Al/Mg/Al is annealed at relative low temperature for a short time while increase when Al/Mg/Al is annealed at relative low temperature for a long time or at relative high temperature. The damping capacities of Al/Mg/Al are influenced by not only Mg and Al layers, but also the interface effect. The impact of interface effect on the damping capacities changes from bad to good with the extension of time and the raising temperature for annealing. 1.5mm Al/3mm Mg/1.5mm Al sheet has the best vibration reduction performance in the vibration test.Mg/glass fiber reinforced epoxy resin laminates were fabricated by vacuum infusion molding process. The reinforced glass fiber has a strong influence on the mechanical properties of laminates, and the yield strength improves obviously with increasing the number of reinforced glass fiber cloth. The yield strength and ultimate strength decrease while the elongation increases when the Mg sheet becomes thicker. But compared to the reinforced glass fiber, the thickness of Mg sheet has a smaller effect on the mechanical properties of laminates. The damping capacities of Mg/glass fiber reinforced epoxy resin laminates basically satisfy rule of mixture of composite at low strain, while not at high strain. This phenomenon depends on the bonding strength. With the number of reinforced glass fiber cloth or the thickness of Mg sheet increasing, the damping capacities of laminates change little. However, the vibration performance of laminates is affected obviously. Changing the number of reinforced glass fiber cloth has an effect on the maximum response displacement by influencing the maximum response acceleration. And changing the thickness of Mg sheet has an effect on the maximum response displacement by influencing the natural frequency. In addition, increasing the number of reinforced glass fiber cloth and the thickness of Mg sheet, the vibration reduction performance both become better.