Quantitative analysis of the residual stress and dislocation density distributions around indentations in alumina and zirconia toughened alumina (ZTA) ceramics
Quantitative analysis of the residual stress and dislocation density distributions around indentations in alumina and zirconia toughened alumina (ZTA) ceramics
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DOI：
10.1016/j.jeurceramsoc.2013.09.021
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发表时间：
2014-03-01
影响因子：
5.7
通讯作者：
Todd, R. I.
中科院分区：
文献类型：
--
作者：
Huang, S.;Binner, J. G. P.;Todd, R. I.
氧化铝、10% 和 20% ZTA 以及 1.5 mol% 氧化钇稳定剂在 1 至 20 kg 的负载下进行维氏压痕测试。对压痕中心和压痕周围应用 Cr3+ 荧光和拉曼光谱，以研究信号的来源、压痕载荷和氧化锆相变对塑性区残余应力和塑性变形的影响。结果表明，在激光散射非常强的情况下，ZTA 材料的深度分辨率非常差，这导致从塑料区下方的地下区域收集到大量信号。还发现，由于氧化锆相变产生了拉伸残余微应力，氧化锆相变降低了塑性区内氧化铝基体中的压缩残余应力（压痕中心除外）。此外，由于相变过程中裂纹扩展和能量吸收的限制，ZTA样品压痕表面的位错密度显着降低。在压痕中心，氧化锆相变被高压应力抑制，因此，在残余应力和位错密度方面，氧化铝和ZTA之间没有观察到显着差异。利用TEM观察发现纯氧化铝的塑性区微观结构与ZTA不同，这与Cr3+荧光结果一致。 (C) 2013 Elsevier Ltd. 保留所有权利。
Alumina, 10% and 20% ZTA with 1.5 mol% yttria stabiliser were subjected to Vickers indentation testing with loads from 1 to 20 kg. Cr3+ fluorescence and Raman spectroscopy were applied to the indent centre and around the indentation in order to investigate the origin of the signal, the effect of indentation loads and zirconia phase transformation on the residual stress and plastic deformation in the plastic zone. The results suggested that with very strong laser scattering, the depth resolution of ZTA materials was very poor, which lead to a very significant amount of the signal being collected from the subsurface regions below the plastic zone. It was also found that zirconia phase transformation reduced the compressive residual stress in the alumina matrix within the plastic zone, except at the indentation centre, due to the tensile residual microstress generated by the zirconia phase transformation. In addition, the dislocation density on the indent surface of the ZTA samples was significantly reduced due to the restriction of crack propagation and energy absorption during the phase transformation process. At the indent centre, the zirconia phase transformation was suppressed by the high compressive stress, therefore, no significant difference between alumina and ZTA in terms of their residual stress and dislocation density were observed. Using TEM observation, it was found that the plastic zone microstructure of pure alumina is different from that of ZTA, which is consistent with the Cr3+ fluorescence results. (C) 2013 Elsevier Ltd. All rights reserved.