Study On The Preparation And Properties Of Open-cell Aluminum Foam With High Porosity And High Specific Strength

The open-cell aluminum foam is a new kind of structural and functional material with wide prospects.It is one of the concerning topics in this research field to investigate and prepare the open-cell aluminum foam with high porosity, uniform pore structure and high specific strength. The gypsum mould investment casting was used to fabricate the high porosity open-cell aluminum foam.In order to fabricate the open-cell aluminum foam with high porosity and high specific strength,the alloying,modification,and T6 heat treatment were used to improve the body strength of open-cell aluminum foams.The fabricating process and compressive properities of open-cell aluminum foams with high porosity and high specific strength were studied,and also the compressive properities of foam-filled tubes prepared by the gypsum mould investment casting. The main research contents and conclusions are as follows:(1) The fabricating process of gypsum mould by polyurethane foam was studied.The best composition range (mass fraction) of gypsum mould was gypsum (65% -75% ), MgS04 (15% -25% ), bauxite (5% -10%); The baking process of gypsum mould was gradual heating, insulation and sub-cooling within the furnace to prepare the soluble gypsum mold with high strength.(2) The fabricating process used to prepare the open-cell aluminum foam by gypsum mould infiltrating casting was studied.It indicates that the main technical parameters during the infiltrating casting process were preheating temperature of 450℃-580℃, pouring temperature of 700℃-780℃, air pressure of 0.3MPa-0.5Mpa. The porosity range of the prepared open-cell aluminum foam with uniform pore structurewas 85% -93.5% .(3) The compressive properties of different open-cell aluminum alloy foams were studied.The test results showed that the stress-strain curves of the high porosity aluminum foams contain three deforming regions,such as elasticity region,plastic collapsing region and densification region.The plastic collapsing region was long and flat,which means the flow stress keep basically unchanged in the l7rger strain context.The compression mechanical properties and energy absorption of ZL101 aluminum alloy foam are higher than ZL102 aluminum alloy foam. The compression mechanical properties and energy absorption of the pure aluminum foam was poor.(4) The effects of the modification and the T6 heat treatment on microstructure,mechanical properties and energy absorption properties of ZL101 aluminum alloy foams were studied.The result showed that morphology of the Si could be refined by modification treatment;The aluminum alloy hardness, compressive mechanical properties and energy absorption performance could be enhanced by modification treatment and T6 heat treatment. The hardness value increased 41% , the yield strength was up to 0.23454MPa, specific strength was up to 0.82×10-3MPa·m3/kg,energy absorption ideality was up to 85% .(5) The compression mechanical properties and energy absorption properties of the open-cell aluminum foam-filled tubes were studied.The specific strength and the specific energy absorption of foam-filled tubes by gypsum mould investment casting were up to 0.1237 MPa-m3/k and 19.39J/g,while comparing to the foam-filled tube by Soluble salt infiltrating casting,the weight of which losed 42.3% .