Research On Foaming Behavior Control And Acoustic Absorption/Insulation Properties Of Magnesium Alloy Composite Foam With Ceramic Microsphere

Magnesium composite foam containing ceramic microspheres is a novel porous material with magnesium alloy skeleton,ceramic microspheres as additives and cellular pore structure embedded in the matrix.Composite foam magnesium has a series of excellent properties such as low specific gravity,high specific strength,specific stiffness,good energy absorption and shock absorption characteristics,good absorption/insulation ability.It is widely used in aerospace,transportation,explosion protection,construction engineering and other fields due to its special matrix material and cellular porous structure.The magnesium composite foam with magnesium alloy as the matrix and ceramic microspheres as composite additive has lower density,higher strength and excellent comprehensive performance than traditional magnesium foam.However,the stability of the foaming process is difficult to control during fabricating magnesium composite foam.The law of the absorption/insulation characteristics of the magnesium composite foam and the influence of the magnesium composite foam on its mechanical properties under different corrosion conditions are not fully understood.In this paper,a modified melting foaming method is adopted,in which AZ31B magnesium alloy is used as a matrix material of magnesium composite foam,hollow ceramic microspheres（CM）is used as a matrix composite additive,and Ca CO₃ powder is used as a foaming agent.By adjusting the type and amount of thickening agent in the stage of thickening process during fabricating magnesium composite foam with modified melting foaming for investigating the effects of different thickening agent calcium（Ca）particles and cerium element（Ce）on the foaming behavior of magnesium composite foam.Meanwhile by adding two kinds of thickening agent in combination,the porosity of the magnesium composite foam can be effectively improved,the pore size of the cell pore structure can be reduced,the roundness of the cell pore structure can be improved,the spatial distribution of the pores and the pore walls are incomplete can be effectively improved.There are defects such as large cracks between the walls of the hole,and the mechanical properties and sound absorption and sound absorption characteristics of the magnesium composite foam are improved.Finally,an excellent magnesium composite foam are obtained,which possess comprehensive mechanical property,sound absorption and sound insulation properties and a fine rounded cellular pore structure;At the same time,from the perspective of the effect of thickening agent on the foaming effect of magnesium composite foam containing ceramic microspheres,the foaming mechanism of composite foam prepared with modified melting foaming method was explored.The addition of different thickening agent will influence the amount and spatial morphology of the solid phase particles in the metal liquid melt on the foaming process and the final foaming effect,thereby obtaining a method for controlling the foaming behavior of the magnesium composite foam.In addition,from the perspective of the application of magnesium composite foam as a functional material,based on the detection results of the sound absorption coefficient and sound insulation of magnesium composite foam with different foaming effects,the effect of foaming effect of magnesium composite foam on its sound absorption and sound insulation properties was investigated for further exploring the absorption/insulation characteristics of magnesium composite foam;The influence of magnesium composite foam on its mechanical properties under different corrosion conditions was also investigated,which provides theoretical and technical support for application process.