Fabrication of Closed-Cell Magnesium Composite Foam with Fine and High Roundness Pore Structure

Though metal foams possess excellent overall performances, its performances behave quite different due to its apparent aperture difference of pores diameter, pores roundness and significant macrostructure flaws, such as sharp edged pores and incomplete cell walls. It is meaningful to reduce macrostructure defects or improve pores structure uniformity of metal foams from the view point of practical applications. In this work, different thickening agents were added into AZ31B magnesium composite foams to balance foaming process and improve the homogeneity of pore diameter, pore roundness and cell wall integrity. The results showed that pore diameter, roundness of the pores and integrity of cell walls were obviously influenced by thickening agents. Based on a large number of experimental results, calcium granules and magnesium cerium intermediate alloy were used to control the number and morphology of solid particles in magnesium melt, and a kind of magnesium composite foams with fine roundness pores and complete cell wall structure were obtained.