Laser Engineered Net Shaping (LENS®) is a Direct Laser Deposition (DLD) additive manufacturing technology that can be used for directly building complex 3D components from metal powders in a combined deposition/laser-melting process. In this study, the effect of LENS process parameters, such as laser power, powder feed rate and traverse speed, on the resultant microstructure, hardness and tensile strength of Ti-6Al-4V components is experimentally investigated. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) are used to characterize the microstructure in terms of grain size and morphology. Relationships between process parameters and the microstructural/mechanical properties are provided. Results indicate that the scale of columnar grains increases with slower laser traverse speeds while other process parameters are maintained constant. The size of the α and β laths increases with higher laser powers and slower traverse speeds. The ultimate tensile and yield strengths of the LENS specimens were found to be higher than those of cast and wrought materials, and this can be generally attributed to the different cooling rates inherent to LENS — which impacts grain size. The percent elongation to failure, however, was consistently lower than that of the wrought material.

This content is only available via PDF.
You do not currently have access to this content.