Multi-Scale Microstructure and Mechanical Properties of High Carbon Eutectic Tantalum Carbide Reinforced with Carbon Nanotubes
Abstract
The overall objective was to develop multiwall carbon nanotube (CNT) reinforced TaC composite with an understanding of mechanical and oxidation properties. Spark plasma sintering was employed to consolidate TaC reinforced with nano B4C and carbon nanotubes. TaC and TaC-1 wt.% B4C powders were consolidated using spark plasma sintering (SPS) at 1850 oC and varying pressure of 100, 255 and 363 MPa. Addition of B4C leads to an increase in the density of 100 MPa sample from 89% to 97%. B4C nano-powder resists grain growth even at high pressure of 363 MPa. Relative fracture toughness increased by up to 93% on B4C addition. TaC-4 wt.% CNT composites were synthesized using two kinds of CNTs, having long (10-20 mm) and short (1-3 mm) length. Addition of CNTs leads to an increase in the density of 100 MPa sample from 89% to 95%. Short CNTs are more effective in increasing the density of the composites whereas long CNTs are more effective grain growth inhibitors. Transverse Rupture Strength of TaC reinforced with shorter CNTs displayed highest strength/density ratio with an improvement of 65% as compared to pure TaC. This was attributed to strengthening caused by CNTs and transformation of shorter CNTs into graphene nano platelets. Oxidation behavior of TaC, TaC-B4C and TaC-CNT composites was evaluated by exposing them to high temperature DC plasma plume at temperatures close to 20000C. TaC and TaC-CNT composites displayed comparable oxidation resistance which was 15 times better than TaC-B4C composites.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 02, 2012
- Accession Number
- ADA562657
Entities
People
- Arvind Agarwal
Organizations
- Florida International University