Effect of Fabrication Method on Microstructure and Properties of Al<SUB>2</SUB>O<SUB>3</SUB>&ndash;TiC Composites

Abstract

Al 2 O 3 -TiC composite powders were prepared by high-energy ball milling (HEBM) and wet-planetary ball milling (WPBM) from different starting materials, and subsequently sintered by Spark Plasma Sintering (SPS). The effect of the fabrication method on the microstructure and properties of Al 2 O 3 -TiC composites was investigated. The results showed that Al 2 O 3 -TiC composites with fine and homogeneous microstructures were prepared by SPS from high-energy ball milled reactants, which had excellent comprehensive properties: bending strength of 944 AE 21 MPa, Vickers hardness of 21:0 AE 0:3 GPa, fracture toughness of 3:87 AE 0:20 MPaÁm 1=2 , and electrical conductivity of 1:2787 Â 10 5 SÁm À1 . The relationship between microstructure and properties and the strengthening and toughening mechanisms was discussed. In comparison with the traditional WPBM route, HEBM was a favorable technique used to produce a high homogeneous microstructure and promising mechanical and electrical conduction properties.

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

“…Researchers have studied the percolation threshold and conductive properties of new advanced ceramics with respect to the proportion of conductive additives [52, 53]. The first studies on samples of composites and nanocomposites of Al 2 O 3 +TiC system produced by spark plasma sintering (SPS) were reported by the group headed by Prof. Zhang [54, 55, 56]. Then, a research group under the supervision of Prof. Torrecillas and Prof. Moya proposed an advanced SPS method assisted by electrical current to produce new nanocomposites of Al 2 O 3 +SiC w +TiC.…”

Graphene nanosheet/titanium carbide composites of a fine-grained structure and improved mechanical properties

“…Our previous work on TiC composites demonstrated Al 2 O 3 -TiC bulk composites by spark plasma sintering (SPS) had much improved mechanical and electrical conduction properties simultaneously [21]. Compared to particles, carbon nanotubes (CNTs) and carbon fibers (C f ) [22] are better to bear the load and prevent crack propagation in matrix for their large aspect ratios.…”

Fine TiC dispersed Al2O3 composites fabricated via in situ reaction synthesis and conventional process

“…The absence of a chemical reaction between Al 2 O 3 and TiC, which leads to the generation of gas, contributes to the high densification of each sample. In situ reaction synthesis is advantageous for obtaining a fine and uniform distribution of the second phase that contributes to densification 24 . Fabrication via in situ reaction of Ti and CNTs yields ATCT composites with a high relative density of nearly 100%.…”

“…Previous studies have reported that in situ reaction synthesis produces composites with more homogeneous microstructures (than those resulting from conventional methods) even from coarse starting powders 22,23 . Zhang et al 24 prepared Al 2 O 3 ‐TiC composites via in situ reaction of Ti (~40 μm) and graphite (~40 μm) and a final TiC size of 200 nm was realized. Lee et al 25 reported that Al 2 O 3 ‐TiC composites with a TiC size of ~2 μm were obtained through in situ reaction synthesis using TiO 2 (<0.5 μm) and graphite (5‐10 μm).…”