Indirect Selective Laser Sintered Fully Ferrous Components – Infiltration Modeling, Manufacturing and Evaluation of Mechanical Properties

Date

2009-09

Authors

Vallabhajosyula, Phani
Bourell, David L.

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Publisher

University of Texas at Austin

Abstract

Commercially available Selective Laser Sintered (SLS) ferrous components contain copper-based infiltrant in a ferrous preform. The choice of infiltrant has led to inferior mechanical properties of these components limiting their use in many non-injection-molding structural applications, particularly at elevated temperature. In the present work, an attempt has been made to replace the copper-based infiltrant considering cast iron as potential infiltrant for its fluidity, hardness and stability at comparatively high temperature. A critical issue associated with the infiltration was diffusion of carbon from the cast iron into the steel preform thereby decreasing its melting temperature and distorting the part geometry. A predictive model was developed which defines the degree of success for infiltration based on final part geometry and depending on the relative density of the preform and infiltration temperature. The model may be extended to other ferrous powder and infiltrant compositions in an effort to optimize the properties and utility of the final infiltrated part. Initial studies were carried out to validate the model by infiltrating SLSed Laserformtm A6 tool steel preforms with ASTM Type I A532 cast iron. The parts were analyzed for geometry, microstructure and hardness. This research was sponsored by the National Science Foundation under Grant #DMI-0522176.

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