Search

Whiskers have been extensively used in ceramics as excellent reinforcing phases during the past decades. Despite in-depth investigation of whisker-reinforced ceramics (WRC), however, the time-consuming, environmentally unfriendly, content design blindness of experimental method as well as pathogenicity of whiskers force people to explore quick and green research approaches. Therefore, this work aims at developing a modeling approach of WRC and predicting the mechanical properties of WRC, thereby compensating for the disadvantages of traditional experimental method. Initially, a modeling approach of WRC based on Voronoi tessellation was presented. Then, taking β-Si 3 N 4w and Si 3 N 4 as research objects, the prediction models of mechanical properties of 0–6 wt% β-Si 3 N 4w -reinforced Si 3 N 4 ceramics (SWRSC) were established. Finally, the effect of β-Si 3 N 4w content on mechanical properties of Si 3 N 4 -based ceramics was discussed, and the enhancement mechanism of β-Si 3 N 4w was revealed. Results indicated that the flexural strength of SWRSC was significantly advanced with increasing β-Si 3 N 4w content. Crack deflection and intergranular fracture induced by β-Si 3 N 4w as well as load-bearing effect of β-Si 3 N 4w were the mainly responsible for the reinforcement of Si 3 N 4 -based ceramics. The enhancement mechanisms, previously observed experimentally, were effectively simulated. The fracture toughness reached a maximum of 6.17 MPa m1/2 when β-Si 3 N 4w amount was 1 wt%, which was approximately 36.50% higher than monolithic Si 3 N 4 ceramic. The predicted value of β-Si 3 N 4w optimal content was consistent with relevant experimental conclusions. When β-Si 3 N 4w content was 3 wt%, the hardness of Si 3 N 4 -based ceramics reached the maximum value of 23.21 GPa. The effectiveness of prediction results and the presented modeling method were confirmed by comparing with related test values. [ABSTRACT FROM AUTHOR]

Herein, a microscale simulation method for the prediction of mechanical properties and composition design of multilayer graphene (MLG)-reinforced ceramic bearings was presented. The method aims at improving the toughness of the ceramic bearings and overcoming the disadvantages of the trial-and-error approach implemented in the research of ceramic bearings. Considering the most widely used Si 3 N 4 ceramic bearing as an example, the microscale models of 1–4 wt% MLG-reinforced Si 3 N 4 ceramic bearings were established using the Abaqus software and on the basis of the ASTM standards. The simulation results obtained through the proposed method and the previously reported experimental results for the mechanical properties demonstrated good agreement. The simulated optimal MLG content value of 1 wt% was consistent with that reported in previous studies, which confirmed the effectiveness of the proposed method. The flexural strength and fracture toughness of the MLG-reinforced Si 3 N 4 ceramic bearings reached the maximum values of 761.77 MPa and 7.23 MPa m1/2 upon the addition of 1 wt% MLG, which were enhanced by 25.85% and 59.96%, respectively, compared with monolithic Si 3 N 4 ceramic bearing. Conversely, the introduction of MLG imparted a softening effect on the Si 3 N 4 ceramic bearings and, therefore, showed reduction in bearing hardness. Moreover, the MLG bridging phenomenon, previously observed experimentally, was revealed through simulation for the first time, which provided an explanation for the toughening mechanism. [ABSTRACT FROM AUTHOR]