Research Status and Prospects of Solidification Microstructure Selection Maps in Metal Additive Manufacturing Processes

Metal additive manufacturing, characterized by its point-by-point and layer-by-layer forming process, enables the efficient and precise fabrication of complex structural components that are difficult to produce with traditional manufacturing techniques. However, the metal additive manufacturing process involves large temperature gradients and rapid cooling rates, constituting a highly non-equilibrium process that may lead to crack formation within the solidified microstructure, thereby influencing the mechanical properties of the material. Consequently, the control of solidification microstructure during metal additive manufacturing is pivotal for designing materials with superior mechanical properties. The solidification microstructure selection map serves as a tool that establishes a mapping relationship between composition/process parameters (used as both horizontal and vertical axes) and solidification microstructure, enabling the prediction and regulation of solidification microstructures in metal additive manufacturing processes. This review provided a comprehensive summary of the current types of solidification microstructure selection maps, outlined their construction methodologies, and summarized the applications of various solidification microstructure selection maps in metal additive manufacturing processes for recent years. Lastly, this review offered insights into the prospects of solidification microstructure selection maps in terms of novel types, innovative construction approaches, and potential application values.