Experimental Study On Mechanical Properties Of The Foamed Steel

Metallic foams as new materials have been widely used in transportation,aerospace,automotive,construction industries and other areas,because of its good mechanical properties and unique pore structure.More and more attention is paid to the study of the mechanical properties of the foam metal.Steel foam as a foam material,has a number of advantages,especially,its high strength and stiffness,so that it has a wide range of uses.In this paper,using iron powder as raw material and ammonium bicarbonate as pore forming agent,after mixing,pressing process,steel foams with different porosity were prepared by sintering at different temperatures by the traditional powder metallurgy method.Scanning electron microscopy(SEM),Archimedes method were been used to detect foam steel material characterization,hardness test and mechanical performance has also been studied.This paper carried out the following works:(1)Different porosities and different sintering temperature of steel foam compression strength were investigated.The compressive strength decreases with the increase of porosity.With 20% and 40% of the pore forming agent sample,when fired at 1200 ? mechanical properties superior to those at 1100 ? and 1300 ?,While 60% of the pore forming agent added samples when fired at 1300 ?,the mechanical properties are better than those at the other two temperatures.(2)The compressive properties of foamed steel samples with different temperature and different porosity were studied,it found that the compressive stress-strain curve can be broadly described as three stages namely elastic stage,stress plateau phase and stage of densification.(3)The effects of different porosity foamed steel tensile properties of the sample,the tensile stress-strain curve of an elastic stage,plastic deformation and fracture stages segment The tensile strength of steel foam,elastic modulus with low porosity will increase and the tensile deformation mechanism differs from the compression.The tensile property of foamed steel is very sensitive to the micro cracks and other defects.(4)Tensile specimen fracture in SEM were found at the tensile fracture material was plastic failure,but the plastic deformation was very small.Foam steel samples with different porosity were hardness testing,hardness of the sample will be found as the pore size varies,hardness decreases when porosity increases.