Thesis
The stability of Ti₂AlC and V₂AlC with Al, and the synthesis of composites in the Al-Ti-B-C and Al-V-C systems
Master of Science (M.S.), Drexel University
01 Jun 2015
DOI:
https://doi.org/10.17918/etd-6531
Abstract
As automotive, aerospace and the power industries increasingly look to carbide and boride based aluminum composites for their high specific strengths and increased thermal stability, it is important to characterize the equilibrium phase relations at temperatures common for processing these composites. Herein, two composite systems were investigated. Composites in the Al-Ti-B-C system were fabricated starting with Al, Ti₂AlC, and B₄C. Composites in the Al-V-C system were fabricated starting with elemental powders. The Ti₂AlC/B₄C powders were mixed in both 50/50 and 75/25 vol. % ratios and cold pressed into 53 % dense preforms. The preforms were pressureless melt infiltrated in the 900 to 1050 °C temperature range with Al. X-ray diffraction, XRD, and scanning electron microscopy, SEM, confirmed that neither Ti₂AlC nor B₄C was an equilibrium phase. The equilibrium phases were found to be Al, TiB₂, Al₃BC, and Al₄C₃ for the more B-rich composite and Al, TiB₂, TiC, and Al₄C₃ for the Ti-rich composite. From these results, the 1000 °C quaternary phase diagram adjacent to the Al-TiB₂-Al₄C₃ triangle and in the Al-rich corner was developed for the first time. In the Al-V-C system, Al-V₂AlC composites were synthesized in situ by quenching from 1000 °C, however fully dense composites have yet to be realized. XRD and SEM investigations indicated a predominately two phase composite (Al and V₂AlC), and that some Al particles did not break their oxide shell. Furnace cooled samples did not form two phase composites. Differential scanning calorimetry was used to determine the instability of V₂AlC with Al below ~ 950 °C. Additionally, the Al-V-C phase diagram was characterized in the Al-rich corner at 800 °C. Al and V₂AlC were found to be in equilibrium with both Al₃V and Al₄C₃, but not with each other.
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Details
- Title
- The stability of Ti₂AlC and V₂AlC with Al, and the synthesis of composites in the Al-Ti-B-C and Al-V-C systems
- Creators
- Matthias Thomas Agne - DU
- Contributors
- Michel W. Barsoum (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) (1970-2026); College of Engineering (1970-2026); Drexel University
- Other Identifier
- 6531; 991014632567604721