Cohesive Element Model for Fracture Behavior Analysis of Al2O3/Graphene Composite Ceramic Tool Material

Abstract

The microstructure model of Al 2 O 3 /graphene (AG) composite ceramic tool material is established based on Voronoi tessellation. The cohesive element method was used to simulate the crack growth of AG. The effect of cohesive parameters at the grain boundary of Al 2 O 3 and graphene on the crack propagation was investigated. The results show that the grain strength of graphene is too high, the crack propagation to graphene grains will be hindered and cannot propagate forward. Cracks tend to spread along the paths where the crack propagation drive force was high and the resistance was low. When the interface strength between Al 2 O 3 and graphene was at the weak interface, the crack propagation path and length were relatively straight and short. The average energy release rate G C is 1.042 × 10 −3 J/m 2 , which is 2.4% higher than that of single-phase Al 2 O 3 ceramic tool materials. However, if the interface strength between Al 2 O 3 and graphene was at the strong interface, the crack propagated along graphene particles for a short distance, consuming a large amount of fracture energy. Furthermore, the crack will deflect around graphene grains, which increases the crack propagation length. The average energy release rate G C is 1.039 × 10 −3 J/m 2 , which is 2% higher than that of single-phase Al 2 O 3 ceramic tool materials.

Effect of the Characteristic Size and Content of Graphene on the Crack Propagation Path of Alumina/Graphene Composite Ceramics

“…In order to form a stress concentration, the initial crack is usually placed in the middle position of the left side of the model. The microtissue model of AG composite ceramic tool material is divided into triangle grid, and the inner cohesion unit is inserted in the adjacent triangle unit [32]. [32].…”

“…The microtissue model of AG composite ceramic tool material is divided into triangle grid, and the inner cohesion unit is inserted in the adjacent triangle unit [32]. [32]. AG, alumina/graphene composite ceramics.…”

“…In order to reduce this effect, the relationship In our previous work, the influence of interfacial bonding strength on the crack propagation path of AG composite ceramics was studied. The results show that the toughening effect is best when the cohesion parameters of alumina grain boundary and intragranular are taken as the cohesion parameters of alumina/graphene phase interface [32]. Therefore, the cohesion parameters of alumina/graphene phase interface are set as the cohesion parameters of the alumina grain boundary (weak interface) and alumina grain interior (strong interface), respectively.…”

“… Microstructure model of composite ceramic tool material [ 32 ]. AG, alumina/graphene composite ceramics.…”

“…(a) 10-50 nm (weak interface) [32] (b) 50-100 nm (weak interface) [32] When the short diameter is 10-50 nm or 50-100 nm, and the long diameter is 800-1200 nm, 1200-1600 nm, 1600-2000 nm, and 2000-2400 nm, respectively, the crack propagation at different interface strengths is simulated.…”