Li_2O-Al_2O_3-SiO_2微晶玻璃加工脆延转变临界条件实验研究

Experimental study of brittle-ductile translation critical condition in Li_2O-Al_2O_3-SiO_2 glass-ceramic machining

介绍了Li2O-Al2O3-SiO2微晶玻璃的加工特点。基于纳米划痕技术对Li2O-Al2O3-SiO2微晶玻璃进行了纳米划痕实验,测得微晶玻璃材料脆延转变临界切削深度和临界载荷的平均值分别为125.6nm和29.78mN。将实验所得临界切削深度值与基于压痕断裂力学模型建立的脆延转变临界切削深度计算值进行了对比,结果表明,T.G.Bifano基于显微压痕法给出的临界切削深度计算值与实验结果差别较大,结合实验结果对其公式进行了修正;基于压痕断裂力学模型建立的延性域磨削临界切削深度计算值与实验结果相差较小,并分析了产生差异的原因。

The features of glass-ceramic processing in the Li2O-Al2O3-SiO2system were introduced.The nano-scratch experiment on glass-ceramic in the Li2O-Al2O3-SiO2system 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 125.6nm and 29.78mN, 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 criticaldepth-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.