Residual stress delaying phase transformation in Y-TZP bio-restorations
Residual stress delaying phase transformation in Y-TZP bio-restorations
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Y-TZP 生物修复中的残余应力延迟相变
DOI：
10.1080/01411594.2011.625347
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
J. Hanan
中科院分区：
文献类型：
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作者：
M. Allahkarami;J. Hanan
为双层陶瓷-氧化锆冠的复杂几何形状设计有利的残余应力可能会防止裂纹的产生，并提高牙齿修复体的机械性能和寿命。除外载外，应力场还取决于加载前的初始残余应力。残余应力是由于层间热膨胀失配和氧化锆晶粒在烧结和冷却过程中的柔顺性各向异性等因素造成的。应力诱导相变使氧化锆中的残余应力得到大范围的松弛，从而改变应力状态。本研究的目的是探讨四斜晶系到单斜晶系的相变与残余应力之间的耦合。采用显微X射线衍射sin 2 θ法测量了从纯四面体开始到完全单斜区域结束的23个点的单载荷破坏冠表面残余应力。一个重要的观察结果是测量的残余应力的显著范围从-400 MPa的压应力到400 MPa的拉应力和高达100%的四斜晶系到单斜晶系的相变。
Engineering favorable residual stress for the complex geometry of bi-layer porcelain-zirconia crowns potentially prevents crack initiation and improves the mechanical performance and lifetime of the dental restoration. In addition to external load, the stress field depends on initial residual stress before loading. Residual stress is the result of factors such as the thermal expansion mismatch of layers and compliance anisotropy of zirconia grains in the process of sintering and cooling. Stress induced phase transformation in zirconia extensively relaxes the residual stress and changes the stress state. The objective of this study is to investigate the coupling between tetragonal to monoclinic phase transformations and residual stress. Residual stress, on the surface of the sectioned single load to failure crown, at 23 points starting from the pure tetragonal and ending at a fully monoclinic region were measured using the micro X-ray diffraction sin2 ψ method. An important observation is the significant range in measured residual stress from a compressive stress of −400 MPa up to tensile stress of 400 MPa and up to 100% tetragonal to monoclinic phase transformation.