Enhancing Toughness in Boron Carbide with Reduced Graphene Oxide

Abstract

Ceramics typically have very high hardness, but suffer from poor toughness. Here, we use graphene to enhance the toughness of bulk boron carbide ceramics. The reduced graphene oxide (rGO) platelets are homogenously dispersed with boron carbide particles after sintering at 1350°C, under high pressure of 4.5 GPa with a multi-anvil apparatus. Fracture toughness of the composites is increased~131% (from~3.79 tõ 8.76 MPaÁm 1/2 ) at 1.5 vol% rGO platelets as a result of a toughing effect of graphene along with a little sacrificing of the hardness and elastic modulus, compared with those of pure boron carbide. The remarkably enhanced fracture toughness in the boron carbide ceramics is associated with graphene sheets crack bridging and graphene interface sliding effect. This study holds much significance for the understanding and development of high-performance graphene reinforcing ceramics.

Electrically conductive graphene nanoplatelet/boron carbide composites with high hardness and toughness

“…GNPs provided a much more efficient toughness enhancement for B 4 C composites compared with other toughening phases including CNTs [17][18][19]24]. A variety of toughening mechanisms has been proposed for GNP/ceramic composites including GNPs pull-out, crack deflection and crack bridging [11][12][13][14][15]. As illustrated in the fracture surface of GNP/B 4 C composites (Fig.…”

“…Compared with its counterpart carbon nanotube (CNT), GNP shows much better dispersability and lower cost. Besides, GNP/ceramic composites exhibited significantly improved toughness compared with monolithic ceramics [11][12][13][14][15]. The toughening mechanisms include sheet pull-out, two-and three-dimensional crack deflection and crack bridging et al [11][12][13][14][15].…”

Preparation and mechanical properties of Si3N4 nanocomposites reinforced by Si3N4@rGO particles

“…Figure 12A shows a representative SEM image of microhardness indentation in the Si 3 N 4 @ Figure 12B shows that the crack propagation path was relatively flat and straight, and no significant toughening mechanisms, such as cracked branching or crack deflection, occurred in the monolithic Si 3 N 4 . [50][51][52] Figure 12D shows that the rGO sheets acting as elastic bridges can effectively bridge the crack, reducing the local stress at the crack tip and blocking the crack propagation and enhancing the toughness of nanocomposites. In this case, the energy required to pull out the two-dimensional rGO sheets was greater than that of the other nanofibers due to the wrinkled rGO sheets wrapping around the Si 3 N 4 grain and the increased contact area between the rGO sheet and the matrix.…”

Sintering dense boron carbide without grain growth under high pressure

“…13,28 The raw powder was first loaded into a mould and pressed into disc shape using a cold press method. High pressure and temperature were performed using a cubic-type multi-anvil apparatus (YL-800t, Guilin Guiye Heavy Industries Co. Ltd., China).…”

“…Detailed experimental procedures can be found elsewhere. 13,28 The raw powder was first loaded into a mould and pressed into disc shape using a cold press method. The asprepared green body was compacted into a molybdenum (Mo) foil and then placed in a capsule made of NaCl-ZrO 2 .…”