Selective laser melting of titanium matrix composites: An in-depth analysis of materials, microstructures, defects, and mechanical properties.

This paper provides an in-depth review of the advancements and challenges associated with Titanium Matrix Composites (TMCs) in Selective Laser Melting (SLM). Material selection, SLM processing parameters, and their influence on the microstructure and properties of TMCs are discussed. The relationship between processing parameters, material characteristics, and the development of defects such as balling, porosity, and cracking is examined. Critical factors influencing the evolution of microstructure and defect formation in TMCs processed by SLM are highlighted. Strengthening mechanisms such as dislocation movements, grain refinement, the Orowan process, and load-bearing capacity are analyzed, and their roles in enhancing hardness, tensile strength, corrosion resistance, and wear resistance are explored. It is indicated by key findings that less than 5 % reinforcement content by volume can significantly enhance mechanical properties, achieving maximum hardness values of approximately 1000 HV and tensile strength close to 1500 MPa. However, this improvement is accompanied by a notable decrease in elongation. The importance of optimizing SLM parameters such as laser power, scan speed, hatch distance, layer thickness, and particle contents to minimize defects and enhance material performance is underscored. Existing research gaps in defect management and material distribution are identified. Future research directions on improving TMCs performance through advanced SLM techniques are suggested.