Experimental study of brittle-ductile translation critical condition in Li2O-Al2O3-SiO2 glass-ceramic machining

The features of glass-ceramic processing in the Li2O-Al2O3-SiO2 system were introduced. The nano-scratch experiment on glass-ceramic in the Li2O-Al2O3-SiO2 system was performed based on nano-scratch technique,and the mean tested values of brittleness-ductility transition critical-depth-of-cut and critical load of glass-ceramic were 125.6 nm and 29.78 mN, respectively. The tested value of critical-depth-of-cut was compared with the calculated value according to the critical condition of brittleness-ductility transition based on indentation fracture mechanics. It was showed that the difference between the calculated value of critical-depth-of-cut given by T. G. Bifano based on micro-indentation and the experimental value was remarkable, thus, the model was corrected in accordance with experimental value; There was no obvious difference between the value of critical-depth-of-cut obtained from experiments and the calculation value of ductile-regime grinding critical condition based on indentation fracture mechanics. In addition, reasons for the difference were also discussed in this paper.