Additive Manufacturing Viewed from Material Science: State of the Art & Fundamentals

Abstract

Additive Manufacturing (AM), also designated as 3D Printing (3DP), is one of the mostvisionary and friendly approaches for flexible manufacturing with conservation of energy andmaterial resources. It is a factory in a box that can generate multiple objects. It requires littlemanpower to bring virtual innovations into the real world. AM for metals can be mechanisticallyassociated with welding. The technique employs a variety of energy sources (laser, electron beam,electric Arc, …), feed stocks (powder, wire and ribbon) and motion kinematics & control(articulated robot and 3-5 axes CNC machine ). From the materials perspectives, akin to fusionwelding in many respects, AM involves a multitude of complex and interacting physical phenomenasuch as heat transfer, fluid flow, discrete and continuum mechanics, sintering, melting,solidification, solid state transformations, grain growth, diffusion, textures etc. The desired processperformance can be achieved by controlling the parameters of energy, feed stock and motion. Theeffect of successive thermal cycles along with the epitaxial relations between substratum anddeposits constitute some of the challenging tasks for developing optimized parts. This paper reviewsthe state of the art and presents some challenges facing metal product development for serviceapplications.