Effect of Additive Ti3SiC2 Content on the Mechanical Properties of B4C–TiB2 Composites Ceramics Sintered by Spark Plasma Sintering

Abstract

B4C–TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering (SPS) at 1900 °C using B4C and Ti3SiC2 as raw materials. The results showed that compared with pure B4C ceramics sintered by SPS, the hardness of B4C–TiB2 composite ceramics was decreased, but the flexural strength and fracture toughness were significantly improved; the fracture toughness especially was greatly improved. When the content of Ti3SiC2 was 30 vol.%, the B4C–TiB2 composite ceramic had the best comprehensive mechanical properties: hardness, bending strength and fracture toughness were 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C–TiB2 composite ceramics was a mixture of transgranular fracture and intergranular fracture. Two main reasons for the ultra-high fracture toughness were the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.

Strengthening boron carbide by doping Si into grain boundaries

“…All QM calculations were performed using VASP package 34,35 with A survey of the published literature shows that process modeling of CMCs has been studied by a number of researchers. Processes that have been modeled include RMI, 15,16 CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltration. 23 Impregnation of alumina matrix in eight-harness satin Nextel 610 fabric has been studied numerically in Ref.…”

“…11 Indeed, amorphous shear bands with a width of 2-3 nm A survey of the published literature modeling of CMCs has been studied by a n ers. Processes that have been modeled CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltrat of alumina matrix in eight-harness satin has been studied numerically in Ref. [ proaches used in the above work general ing the flow of a high viscosity resin thr and modeling the chemical reactions and during processing.…”

“…This suggests that adding Si or P to the grain boundaries might improve ductility. Several approaches, such as microalloying, [12][13][14][15][16] stoichiometry control, [17][18][19] and addition of a second phase, [20][21][22] have been proposed to mitigate amorphous shear band formation. For microalloying, both non-metal dopants (P 23 and Si 24 ), as well as metal dopants (Li, 14,15 Mg, 12,16 and Ti 13 ) may decrease amorphization in B 4 C. Both experimental and theoretical studies have suggested that boron enrichment is helpful to mitigate amorphization.…”

High hardness (TiZr)C ceramic with dislocation networks

“…density, forming composites, and reinforcing by fibers or whiskers are conventional methods commonly used to improve ceramics' mechanical properties. [5][6][7][8][9] Unlike metal alloys, ceramics with ionic or covalent bonding seldom employ defects of nanotwins or dislocations to enhance mechanical properties due to the high energy for those defects' formation and movement. 10 Nevertheless, inspired by the fact that dislocations could enhance the strength of alloys, 11,12 the prefabrication of dislocations to enhance the hardness of ceramics has attracted much attention.…”