Development of a New Method to Fabricate Titanium Metal Matrix Composites via LENS with Improved Material Properties Public

A new fabrication method was developed utilizing laser near-net shaping (LENS) additive manufacturing technology to produce novel bulk metal matrix composites (MMC) with dual continuous immersed phases (DCIP) in order to improve material properties. The nature of using LENS to create DCIP samples has several advantages over alternative MMC fabrication methods which allow the creation of bulk parts with material property combinations not found in existing engineered or natural materials. DCIP samples were produced using near-β and α/β titanium alloys as the constituent phases. The sample’s microstructure is explored via optical microscopy and Vickers hardness testing. A methodology is presented to select processing parameters to avoid defects. The fabrication method and process development was found to be successful in creating a bulk samples free from processing defects. Vickers hardness testing revealed considerable variability in hardness values across the sample and within individual deposits suspected to be a result of substantial intermixing between adjacent hatches and layers. Further refinement of process parameters is expected to decrease intermixing and hardness variability. Epitaxial grain growth was attenuated by the DCIP morphology as compared to bulk laser deposited Ti-6Al-4V samples. Additional geometrical considerations are considered. The practicality, potential, and impact of scaling this process to an industrial scale is explored and discussed. Present and future possible uses of this technology are given.

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