DIRECT LASER DEPOSITION OF POROUS STRUCTURES AND GRADIENT METAL-CERAMIC COMPOSITE COATINGS
Direct laser deposition is an additive manufacturing technique capable of producing complex geometries, bond different materials, repair broken parts, and add protective coating. In the present study it is used to make micro-porous scaffolds and apply protective vanadium and niobium carbide coatings. Micro-porous metal filters are a difficult thing to make but are required for many applications. In this study it was hypothesized that laser engineering net shaping (LENS) could be used to make porous Ti6Al4V scaffolds with an interconnected micro-porous structure. This proved to be true with cylinders made to have 15.9% porosity, and a pore size less than 100μm. These structures were made by only altering processing parameters, which yielded a scaffold with obstructed random pore interconnectivity. The scaffolds had a compressive strength of 645-556MPa and martensitic like α' grains. Another study was done to apply hard niobium and vanadium carbide surface coatings to stainless steel. The objective was to used LENS to deposit stainless steel coatings with added carbides to eventually make a gradient coating with increased protective qualities. Parts that have suffered material loss from abrasive wear or cavitation could have material added back as well as add a protective coating at the same time. Compositions ranging from 5% to 100% of the carbides were mixed with stainless steel. The coatings were then deposited on a stainless steel 304 substrate individually, as well as in a series to make a gradient structure. These coatings all increased hardness, wear resistance, and 100%VC significantly increased the materials resistance to damage from abrasive water. The carbides integrated into the SS304 matrix on the grain boundaries making a metal ceramic composite. These precipitates left residual stress in the structure which increased the hardness and wear resistance. The study proved that the addition of these carbides did increase the protective qualities and could make a gradient coating with properties tailored to the user’s preference.
- Research Organization:
- Hydropower Foundation
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Water Power Technologies Office
- DOE Contract Number:
- EE0006506
- OSTI ID:
- 1648149
- Country of Publication:
- United States
- Language:
- English
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