Abstract
Abstract: The homogenous dispersion of particles in a metal matrix is of critical importance to the design and manufacturing of particle-reinforced metal matrix composites (MMCs). This work studied the effects of increasing melt viscosity via microalloying and increasing cooling rate on the dispersion of particles in an aluminum-based MMC. A CALculation of PHAse Diagrams (CALPHAD)-based viscosity model was developed for the Al-Ni binary system. This viscosity model was coupled with a particle-capture model to explore particle/metal interactions during solidification. Three composites (Al + TiCp) with and without Ni were cast at different cooling rates. The first composite without Ni cast at a lower cooling rate showed macro-segregation and agglomeration of TiCp along the grain boundaries. The second composite without Ni cast at a higher cooling rate exhibited grain refinement and reduced macro-segregation of TiCp. The third composite alloyed with 1 wt pct Ni and cast at the same higher cooling rate had an improved distribution, and particles > 2 µm in size were captured in the grains. The composite with 1 wt pct Ni had a 45 pct higher melt viscosity and a 31 pct lower critical velocity for capture of TiCp, demonstrating a synergetic effect of increasing viscosity and cooling rate on improving particle dispersion in MMCs.
Original language | English |
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Pages (from-to) | 3736-3747 |
Number of pages | 12 |
Journal | Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science |
Volume | 50 |
Issue number | 8 |
DOIs | |
State | Published - Aug 15 2019 |
Externally published | Yes |
Funding
The authors gratefully acknowledge the financial support from the Melt R2-2 project funded by LIFT (Lightweight Innovations For Tomorrow), a Manufacturing Institute under the contract from the Office of Naval Research. We thank Prof. Brajendra Mishra and his graduate student Jeremy Fedors (Worcester Polytechnic Institute) for providing the pure Al + TiC samples. We also thank graduate students Emre Cinkilic, Yan Lu, and Xuejun Huang (The Ohio State University) for their help with discussions and technical contributions. p The authors gratefully acknowledge the financial support from the Melt R2-2 project funded by LIFT (Lightweight Innovations For Tomorrow), a Manufacturing Institute under the contract from the Office of Naval Research. We thank Prof. Brajendra Mishra and his graduate student Jeremy Fedors (Worcester Polytechnic Institute) for providing the pure Al + TiCp samples. We also thank graduate students Emre Cinkilic, Yan Lu, and Xuejun Huang (The Ohio State University) for their help with discussions and technical contributions.