In the present work, we investigate the effects of the size and volumetric fraction of Zr2Cu on the density and mechanical strength of liquid-reactive sintered W/MWCNTs/ Zr2Cu composites. Composite powders are formed by mechanical ball-milling and are sintered into a high density composite at 1400 C. During sintering, two major reactions occur: 1) C atoms in the MWCNTs reacted with the W matrix to form WC; 2) Zr in the Zr 2Cu liquid phase, which flows through the capillaries between particles, reacts with WC in the W matrix to form ZrC. Based on our results, higher density composites with finer ZrC reinforcements are successfully produced using sub-micron size Zr2Cu powders. In addition, the amount of Zr2Cu is varied, and the optimal volumetric fraction of Zr 2Cu that maximizes the hardness of the composite (1180 Hv) is equal to 30 vol.%. When the Zr2Cu content is less than the critical value, and the density of the composite is too low due to an insufficient amount of liquid. The hardness of the composite decreases when the Zr2Cu content is greater than 30 vol.%, because excess liquid yields a network structure of WC, ZrC, and Zr. The experimental results also reveal that the sintering time required to reach the maximum hardness (1180 Hv) significantly decreases as the size of Zr2Cu is reduced from micron-scale to nano-scale.
|Number of pages||7|
|Journal||International Journal of Refractory Metals and Hard Materials|
|Publication status||Published - 2014 Mar|
Bibliographical noteFunding Information:
This work was supported by the Agency for Defense Development in Republic of Korea .
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry