牙科氧化锆陶瓷压痕尺寸效应模型评价

Evaluation of indentation size effect models of dental zirconia ceramics

目的:在分析现有氧化锆(Yttria partially stabilized zirconia,Y-TZP)陶瓷压痕尺寸效应规律和评价现有压痕尺寸效应模型基础上,推荐能准确描述Y-TZP陶瓷压痕尺寸效应的模型。方法:收集五种Y-TZP陶瓷压痕尺寸效应实验数据,回顾现有压痕尺寸效应模型,然后对现有压痕尺寸效应模型进行分析和评价。结果:描述Y-TZP陶瓷正压痕尺寸效应,即硬度随压痕深度增大而减小并逐渐趋于固定值,Bull、Hays-Kendal、修正Nix-Gao、Nix-Gao、Li-Bradt93、Li-Bradt96和Meyer模型的总平均相关系数(T-R;)分别为0.9885、0.9805、0.9136、0.9086、0.9198、0.7808和0.7169;只有Bull和Li-Bradt96模型能体现Y-TZP陶瓷硬度随压痕深度增大先增后减并逐渐趋于固定值,即先逆后正压痕尺寸效应,相关系数R^(2)分别为0.5380和0.4064。结论:推荐使用T-R^(2)较大的Bull或Hays-Kendal模型描述Y-TZP陶瓷正压痕尺寸效应,但是目前尚没有模型能准确描述Y-TZP陶瓷先逆后正压痕尺寸效应,实验最小压痕深度远小于晶粒大小是产生逆压痕尺寸效应原因。

Objective:Based on the analysis of existing yttria partially stabilized zirconia(Y-TZP)ISE and the evaluation of existing ISE models,models which can accurately describe the indentation size effect(ISE)of Y-TZP ceramics were recommended.Methods:The experimental data of ISE were collected from five kinds of Y-TZP.The existing ISE models were reviewed,and then analyzed and evaluated.Results:To describing the normal ISE,which the hardness of Y-TZP decreased with the increase of indentation depth and gradually tended to a fixed value,T-R^(2) of Bull,Hays-Kendal,Modified Nix-Gao,Nix-Gao,Li-Bradt93,Li-Bradt96 and Meyer models were 0.9885,0.9805,0.9136,0.9086,0.9198,0.7808 and 0.7169,respectively.The first reverse and then normal ISE,which the hardness of Y-TZP first increased and then decreased with the increase of indentation depth and gradually tended to a fixed value,could be reflected by Bull and Li-Bradtr96 models,R^(2) of these models were 0.5380 and 0.4064,respectively.Conclusions:The Bull or Hays-Kendal models with larger T-R^(2) is recommended to describe the normal ISE of Y-TZP,but none of the current models can accurately describe the first reverse and then normal ISE of Y-TZP.The mechanism of is that the experimental minimum indentation depth is much smaller than the grain size.