Study On Fabrication And Properties Of The Foamed Magnesium Materials

This paper explores the fundamental processes of the melt foaming technology, analyzes the influence of the addition order of the thickener and the blowing agent, the volume fraction of thickener, the mass fraction of blowing agent and the holding time to the porosity and pore structure of foamed magnesium, and ultimately summarizes the rule of prepared foamed magnesium using melt foaming method under the experimental conditions: the preparation process of first adding the thickener and then joining the blowing agent can get a higher porosity; With the increase of the thickener volume fraction, the porosity of the magnesium foaming sample increases at first and then decreases, in this experiment, 15% of the volume fraction of thickener is best; With the increase of the mass fraction of blowing agent, the porosity of the magnesium foaming sample is first increases and then decreases, in this experiment, 1.5% of the mass fraction of blowing agent is best; With the increase of the holding time, the porosity of the magnesium foaming sample is increased gradually, But if the holding time is too long, the holes will be connected with each other and has obvious flaws appeared, in this experiment, 15 min of the holding time is best.On the basis of the optimum process parameters, continue to explore the advantage of Ca CO3 compared with Mg CO3 as the foaming agent, then found that because Ca CO3 has the advantage of higher reaction temperature and slower decomposition speed, the various steps in the preparation process can be controlled more easily and the preparation of technology has a better reproducibility, so Ca CO3 is a better foaming agent than Mg CO3.Finally, we tested the compression properties, thermal conductivity properties, damping properties and impact properties with different porosity of the foamed magnesium. After making compressing test of the foamed magnesium, we can find that the compression curve shows the typical deformation of three phases: initial stage is elastic deformation, and as the porosity increases, the compression σsc also reduces; Subsequent the stress-strain curve come into the plastic platform area, and the curve appear fluctuations; finally the compression stress increases with the strain dramatically; at the same time we can get that with the increase of the cell-size, the plastic platform area in the stress- stain curve fluctuates more and more significantly, however the small cell-size foamed magnesium sample has a gentle plastic platform area and a better performance; after the thermal performance test of the foamed magnesium, we can find that with the increase of the porosity, the thermal conductivity of the foamed magnesium material gradually reduced, and the high porosity foamed magnesium materials can be used as insulation material and play a weight loss effect; After the damping properties test of the foamed magnesium, we can find that compared to the matrix material, the damping properties of the foamed magnesium has a little increase; after the impact test of the foamed magnesium, we can find that foamed magnesium material happen very small deformation can generate good shock buffering effect, suggests that it has a wide application prospect as the shock impact resistant materials.