Metal injection moulding of iron based syntactic foams

Metal foams based on aluminium have already been implemented in industry as light-weight construction or crash absorbing components. However, their compression strength of 5-30 MPa is not sufficient e.g. for applications with high deformation loads. New approaches to obtain syntactic foams based on iron or steel materials can offer remedy. In this paper the development of new iron based syntactic foams by applying the metal injection moulding (MIM) technology is presented. In this process Fe powder is mixed with microscopic glass hollow spheres and cenospheres. The mixture is then homogenised with a special binder system and injection moulded on conventional moulding machines. The binder is removed and the syntactic Fe foam is sintered at 900 °C. With this technology tensile test specimens were manufactured in series for foams containing up to 10 wt% hollow spheres in the iron matrix. Material properties of the respective materials were measured and as a result compression strengths of up to 290 MPa were obtained.