Cano-Crespo Rafael, Retamal César, Lagos Miguel, Cumbrera Francisco Luis
Departamento de Física de la Materia Condensada, Universidad de Sevilla, Apartado 1065, 41080 Sevilla, Spain.
Facultad de Ingeniería, Universidad de Talca, Campus Los Niches, Camino a los Niches Km 1, Curico 3340000, Chile.
Materials (Basel). 2022 Feb 14;15(4):1396. doi: 10.3390/ma15041396.
The superplastic behavior of alumina-based nanostructured ceramics (AlO) is an important issue in the world of materials. The main body of this paper is an analysis of the creep behavior of polycrystals, with grain boundary sliding as the main deformation mechanism at high temperatures. Concomitant accommodation of grain shapes to preserve spatial continuity has a comparatively small effect on the strain rate. The constitutive equations for small deformations, relating strain and strain rate, derived from two models for grain sliding, are compared with the experimental data with their respective uncertainties. The data follow from experiments on the plastic deformation of alumina composites reinforced, on the one hand by graphene oxide, and on the other hand by carbon nanofibers sintered by SPS. The results show good agreement between experiment and theory for these advanced ceramics, particularly for one of the assumed models. The values obtained of for model A were in the interval 0.0002-0.1189, and for model B were in the interval 0.000001-0.0561. The values obtained of for model A were in the interval 0.9122-0.9994, and for model B were in the interval 0.9586-0.9999. The threshold stress was between (3.05 · 10-25.68) MPa.
氧化铝基纳米结构陶瓷（AlO）的超塑性行为是材料领域的一个重要问题。本文的主体是对多晶体蠕变行为的分析，其中高温下以晶界滑动为主要变形机制。伴随晶粒形状的调整以保持空间连续性对应变速率的影响相对较小。从两种晶粒滑动模型推导得出的、与应变和应变速率相关的小变形本构方程，与其各自的不确定性一起与实验数据进行了比较。这些数据来自对一方面由氧化石墨烯增强、另一方面由放电等离子烧结的碳纳米纤维增强的氧化铝复合材料的塑性变形实验。结果表明，对于这些先进陶瓷，实验与理论之间具有良好的一致性，特别是对于其中一个假定模型。模型A得到的 值在0.0002 - 0.1189区间，模型B得到的 值在0.000001 - 0.0561区间。模型A得到的 值在0.9122 - 0.9994区间，模型B得到的 值在0.9586 - 0.9999区间。阈值应力在(3.05·10 - 25.68)MPa之间。
