An Experimental Study on Mechanical Modeling of Ceramics Based on Microstructure

Ya-Nan Zhang,Xiao-Fei Song,Jian-Jun Liu,Bin Lin,Jie Key

doi:10.3390/app5041337

Abstract

The actual grinding result of ceramics has not been well predicted by the present mechanical models. No allowance is made for direct effects of materials microstructure and almost all the mechanical models were obtained based on crystalline ceramics. In order to improve the mechanical models of ceramics, surface grinding experiments on crystalline ceramics and non-crystalline ceramics were conducted in this research. The normal and tangential grinding forces were measured to calculate single grit force and specific grinding energy. Grinding surfaces were observed. For crystalline alumina ceramics, the predictive modeling of normal force per grit fits well with the experimental result, when the maximum undeformed chip thickness is less than a critical depth, which turns out to be close to the grain size of alumina. Meanwhile, there is a negative correlation between the specific grinding energy and the maximum undeformed chip thickness. With the decreasing maximum undeformed chip thickness, the proportions of ductile removal and transgranular fracture increase. However, the grinding force models are not applicable for non-crystalline ceramic fused silica and the specific grinding energy fluctuates irregularly as a function of maximum undeformed chip thickness seen from the experiment.

Highlights

Because of their the superior mechanical and thermal properties, advanced ceramics have found increasing applications in aerospace industry, military industry, vehicle engineering and so on
The results showed that Removal rate was proportional to grain size l1/2 and load p2
Large studies indicate that the fracture strength of crystalline grains is bigger than grain boundary. They found that the mechanism of material removal in alumina is identified as intergranular fracture and grain dislodgement resulting from grain boundary microcracking irrespective of the grain size

Summary

Introduction

Because of their the superior mechanical and thermal properties, advanced ceramics have found increasing applications in aerospace industry, military industry, vehicle engineering and so on. Hecker et al derived a predictive grinding force per grit equation based on the relation between the abrasive indentation model and hardness [8]. Many indentations and scratch experiments of alumina were conducted on removal mechanism, material removal volume, damage, and so on as a function of grain size [5,13,14]. Large studies indicate that the fracture strength of crystalline grains is bigger than grain boundary They found that the mechanism of material removal in alumina is identified as intergranular fracture and grain dislodgement resulting from grain boundary microcracking irrespective of the grain size. This work dedicates to talk about influences of the relation between grain size and maximum undeformed chip-thickness on grinding force modeling and removal mechanisms of crystalline ceramics and non-crystalline ceramics. The grinding force modeling can be improved by considering both the grinding parameters and materials microstructure

Properties of Workpieces

Grinding Experiment

Results and Discussion

Conclusions