State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an 710032, China.
J Mech Behav Biomed Mater. 2018 Feb;78:28-35. doi: 10.1016/j.jmbbm.2017.11.003. Epub 2017 Nov 3.
Post-crystallization annealing above the T was applied to a lithium disilicate glass-ceramic with microstructure consisting of glassy matrix and rod-like lithium disilicate crystals, effect of the annealing on the mechanical behavior was investigated. Flexural strength and VIF toughness of the glass-ceramic unexpectedly decreased after the annealing. The mechanical behavior variation was understood based on residual micro-stress analysis. Coefficient of thermal expansion for the glassy matrix presented a tendency to increase after the annealing, which would enlarge the thermal expansion mismatch between the glassy matrix and the lithium disilicate crystals. As a result, the residual micro-stresses in the glass-ceramic abnormally increased with increasing the annealing time. The mechanical property degradation was attributed to the annealing-induced increase of the residual micro-stresses.
将高于 Tg 的后结晶退火应用于一种具有玻璃基质和棒状二硅酸锂晶体的微观结构的二硅酸锂玻璃陶瓷，研究了退火对机械性能的影响。出乎意料的是，玻璃陶瓷的弯曲强度和 VIF 韧性在退火后下降。基于残余微应力分析，理解了机械性能变化。玻璃基质的热膨胀系数在退火后呈现出增加的趋势，这将增大玻璃基质和二硅酸锂晶体之间的热膨胀失配。结果，玻璃陶瓷中的残余微应力随着退火时间的增加而异常增加。机械性能的退化归因于退火引起的残余微应力的增加。
