| Autor: |
Tian-Yi Hu, Mian-Yi Yao, Dong-Li Hu, Hui Gu, Yu-Jin Wang |
| Jazyk: |
angličtina |
| Rok vydání: |
2019 |
| Předmět: |
|
| Zdroj: |
Journal of Materiomics, Vol 5, Iss 4, Pp 670-678 (2019) |
| Druh dokumentu: |
article |
| ISSN: |
2352-8478 |
| DOI: |
10.1016/j.jmat.2019.05.001 |
| Popis: |
Phase relation and microstructure evolution in the pressure-less sintered TiB2‒TiC ceramics preceded with mechanical alloying were systematically studied by a combination of SEM analysis. WC debris from milling balls promotes sintering by dissolving into the TiC phase to achieve dense microstructures at 1600 °C. Variation of W solution in TiC grains exposes two types of core‒rim structures, with no or more W in dark and white cores respectively but with common medium W in both rims. Diminishing white-cores reveal an exchange reaction between WC and TiC via mechanical alloying to form the Ti1-zWzC phase prior to sintering. The dark-cores inherit from the as-milled TiC power to further enable the reprecipitation of rims from a mixed liquid-phase, which facilitated also the anisotropic growth of TiB2 grains. The dark-cores grow persistently in the second-step at 2000 °C enabled by this liquid-phase, which coarsens the TiB2 grains too. With more alloyed phase, sintering was insufficient at 1500 °C with only the surface fluidity from the primary powders, and the second-step sintering increased the fluidity in the liquid-phase to fully densify the binary microstructure. Re-distribution of the alloyed W by two-step sintering rationalizes the evolution process of the binary microstructures and leads to better understanding of the mechanical behaviors. Keywords: TiB2‒TiC ceramics, Mechanical alloying, Core‒rim structures, Liquid-phase sintering, Microstructure‒, Property relationship |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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