Preparation And Compression Property Of Foamed Magnesium Alloy

Foamed metal as a new type of porous function material, due to its special structure and performance characteristics, will be widly applied in high-technic areas and general industrial fields. The superior mechanical properties of magnesium alloy will effectively used, product development and applying field of foamed metal and magnesium alloy be widen by preparing foamed magnesium.Foamed magnesium was successfully prepared by vacuum infiltration casting, in this process NaCl particles were adopted. The die was rationally designed. The particle cleaning technic was presented. Three parameters (preheating temperature of particle, pouring temperature of Mg and Vacuum degree) of infiltration process were theoretically analyzed and determined.Based on the vacuum infiltration process, sponginess Mg alloy was prepared using porous plaster mold made with sponge matrix.Foamed metals have good shock and energy absorption property. It is important to study its compression deformation behavior and energy absorption property. In this paper the quasi-static compression property of foamed Mg was studied.The experimental results showed that:(1) In vacuum infiltration process, NaCl particles was selected as filling material and was compacted in mold layer by layer. Three pouring parameters , preheating temperature of particle, pouring temperature and vacuum degree were determined as 550～600℃,730℃and -0.02～-0.04Mpa, respectively. Particle cleaning process was improved to resisting NaCl corrosion, which included water washing and brushing, soaking self-mading solution, high pressure water washing and high pressure air drying. The samples were obtained with 0.1-1.6mm pore diameter and 50%-70% porosity.(2) Sponginess magnesium alloy was prepared by using porous plaster mold. In this process, the adding quantity of MgSO4 was 16wt% of plaster, the ratio of water and solid material 0.55, the mixing time 2-3min. The plaster mold was heated and baked step by step. Three pouring parameters , preheating temperature of particle, pouring temperature and vacuum degree were determined as 550℃,730℃and -0.04Mpa, respectively. Plaster was cleaned by water washing and virbation. The inertia gas was adopted to prevent explosion and combustion in pouring. The sample structure inherited the sponge structure, which pore diameter was 5mm and porosity 94%.(3) The compression deformation characteristic of foamed Mg alloy and the effects of porosity, material and pore size on comprssion property were investigated, which can provide necessary theory for the application of energy absorption. The deformation type was brittle fracture. The stress-strain curves were divided into three regions: elastic region, yield region, densification region and their shapes were influenced by material, porosity and pore size to varing degrees. The material has the most influence on compression property. To the same material, with increasing relative density, the yield stress increased and yield region decreased. Pore size had low effect to yield strength.