Fatigue and subcritical crack growth in ZrO2-bioglass ceramics
Fatigue and subcritical crack growth in ZrO2-bioglass ceramics
复制标题
DOI：
10.1016/j.ceramint.2012.08.093
复制
发表时间：
2013-04
影响因子：
5.2
通讯作者：
L. A. Bicalho;C. Baptista;R. Souza;C. Santos;K. Strecker;M. Barboza
中科院分区：
文献类型：
--
作者：
L. A. Bicalho;C. Baptista;R. Souza;C. Santos;K. Strecker;M. Barboza
研究了牙科修复用生物玻璃掺杂的氧化锆基陶瓷(Y-TZP)的性能。在1300℃下，分别加入3%或5wt%的3CaO·P2O5-SiO_2-MgO生物玻璃，在1300℃下烧结2小时。用X射线衍射仪(X射线衍射仪)分析了样品的物相组成，用扫描电子显微镜(SEM)对样品的微观结构进行了分析。用维氏压痕法测定了材料的硬度和断裂韧性，用四点弯曲试验测定了材料的抗弯强度和抗疲劳性能。力学性能测试表明，在所采用的烧结条件下，样品达到了较高的致密度。X-射线衍射仪分析表明，主晶相为四方相的氧化锆。添加3%和5%生物玻璃的烧结体的硬度分别为1167和1134HV，断裂韧性分别为6.3和6.1MPam1/2，抗弯强度分别为453和636 MPa。疲劳结果显示出较大的散射性，这归因于二次玻璃相在氧化锆基质中的不均匀分布。玻璃的不均匀分散可能会导致应力梯度的形成，这可能是疲劳试验期间裂纹萌生及其各自的亚临界扩展的原因。确定的疲劳极限优于咀嚼过程中产生的应力，使其在牙科修复中的应用成为可能。对255、270和285 Mpa的平均应力水平下的疲劳结果进行了威布尔统计，以计算亚临界裂纹扩展。计算了在恶劣循环压力条件下的预期寿命为20年以上。
This work investigates the characteristics of ZrO2based ceramics (Y-TZP) doped with bioglass developed for dental prostheses. Powder mixtures composed of zirconia and 3 or 5wt% of 3CaO·P2O5–SiO2–MgO bioglass were sintered at 1300°C for 2h. The samples were characterized by their phase composition using X-Ray diffraction (XRD) and analysis of their microstructure by scanning electronic microscopy (SEM). Hardness and fracture toughness were evaluated using the Vickers indentation method, while bending strength and fatigue resistance were determined using the four-point bending testing. The mechanical properties indicate that the samples achieved high density under the applied sinter conditions. X-ray diffraction analysis revealed tetragonal ZrO2as a major crystalline phase. Hardness, fracture toughness and bending strength of the sintered samples containing 3% or 5% bioglass were 1167and 1134HV, 6.3 and 6.1MPam1/2and 453 and 636MPa, respectively. The fatigue results presented large scattering, which is attributed to a heterogeneous distribution of the secondary glassy phase in the zirconia matrix. The non-uniform dispersion of the glass may result in the formation of stress gradients, possibly responsible for crack initiation and their respective subcritical growth during fatigue testing. The fatigue limit determined was superior to stresses developed during mastication, turning its use in dental prostheses viable. Weibull statistics were applied on the fatigue results obtained at average stress levels of 255, 270 and 285MPa in order to calculate the subcritical crack growth. A life expectancy of over 20 years under severe cyclic pressure conditions has been calculated.