Selective Laser Melting of Boron Nitride Nanoplatelet-Reinforced Titanium Composites
Abstract
Selective laser melting (SLM) is limited by the lack of composite powders available for purchase. This thesis focused on additively manufactured boron nitride nanoplatelet-reinforced titanium composites that maintain the structural integrity of traditional titanium alloys while promoting an increase in hardness and wear resistance. Boron nitride nanoplatelets (BNNP) were used as reinforcements due to their two-dimensionality and large surface areas. These properties aid in alloying with the spherical titanium powders without significant powder morphology. Titanium alloy (Ti-64) was researched to form a baseline of the properties expected and was used as the control. Titanium metal matrix composites (Ti-MMC) were produced using spatial arrays created using bulk Ti-64 mixed with Ti-BNNP composites forming regional microstructures. These spatial arrays consist of 0.5, 1.0, and 2.5 vol percent composites with dispersions of reinforcement rich and reinforcement deficient regions. Each part was fabricated using SLM, and heat treatment took place upon fabrication to compare microstructure and porosity changes. Hardness testing and dry sliding tribological testing was performed to evaluate mechanical properties and wear resistance exhibited by Ti-MMC reinforced with nitrides. The addition of BNNP, even at low volume percentages (0.5vol percent), resulted in an increase of localized hardening with the max hardening increase of 36% (2.5 vol percent).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2021
- Accession Number
- AD1151025
Entities
People
- Marian A. Jester
Organizations
- Naval Postgraduate School