In-Process Fabrication of Carbon-Dispersed Aluminum Matrix Composite Using Selective Laser Melting

Abstract

We have investigated the basic characteristics of C/Al composites prepared in-process via selective laser melting (SLM) using a mixed powder of pure aluminum and short carbon fiber. Initially, the relationship between the relative density of the SLM composites and laser scan conditions was systematically investigated. The SLM composites were densified by applying laser scan conditions with high input energy density (>100 J/mm3). The densified SLM composite showed excellent hardness together with low thermal conductivity, due to the generation of an Al4C3 phase and increased solid-solution carbon in the α-Al matrix via the reaction between aluminum and carbon during laser irradiation. This reaction could be inhibited in SLM composites fabricated from another mixed powder of copper-plated carbon fiber and pure aluminum powder since laser absorptivity significantly decreased due to the high reflectivity of the copper plate on the carbon fiber. By investigating the Cu plated C/Al SLM composites, we demonstrated that the thermal management material having anisotropic thermal conductivity could be fabricated by controlling the carbon dispersion by using a unidirectional laser scanning pattern.

Keywords

• selective laser melting (SLM)
• metal matrix composite (MMC)
• aluminum alloy
• carbon fiber
• microstructure