Additive manufacturing of in situ metal matrix composites

While laser additive manufacturing is becoming more and more important in the context of advanced manufacturing for the future, most of the current efforts are focusing on optimizing the required parameters for processing well-matured alloys from powder feedstock to achieve reproducible properties, comparable to, or better than, their conventionally processed counterparts. However, laser additive manufacturing also opens up a new avenue in terms of processing novel alloys and composites that are difficult to process using traditional processing routes. Metal matrix composites (MMCs) are the new class of advanced materials in which rigid ceramics reinforcements exhibiting excellent strength as well as elastic modulus are embedded in a ductile metal or alloy matrix to overcome the inadequacy of metals and alloys in providing both strength and stiffness to the structure. Metal matrix composites possess excellent physical as well as mechanical properties, which makes them suitable for structural, automotive and aerospace applications. MMCs are mainly classified into two categories, ex-situ, and in-situ based on the formation of ceramic reinforcement during their processing. In situ reactions during laser additive processing takes place either between elemental blend powder or between elemental blend powder and reactive gases (e.g. nitrogen, oxygen, etc.). This chapter mainly discuss on laser additive manufacturing of in situ metal matrix composites. Laser additive processing of nickel, aluminum, and titanium matrix composites are the focus of this chapter.