Twin lamellas, were observed in transparent AlON ceramics in our previous work. In this work, the influence of the twin lamellas on mechanical strength was evaluated and its mechanism was investigated by SEM, EBSD, and HRTEM. Both the crystallographic direction and the space direction of a crack will deflect when it propagates across a twin lamella. The dynamic mechanism is that the dislocation propagation in front of the crack tips is blocked by the twin boundaries. Because the fraction of twin boundaries increases with grain size in transparent AlON ceramics, the strengthening effect becomes more notable for large-sized samples resulting in inverse Hall-Petch relation. It is a potentially useful way to advance the mechanical properties of transparent AlON ceramics by controlling the content of twin lamellas.

在我们先前的工作中，在透明的AlON陶瓷中观察到了双片。在这项工作中，评估了孪晶薄片对机械强度的影响，并通过SEM，EBSD和HRTEM研究了其机理。裂纹的晶体学方向和空间方向都将在其穿过双晶薄片传播时发生偏转。动力学机制是裂纹尖端前的位错扩展被孪晶边界所阻挡。由于在透明AlON陶瓷中孪晶边界的分数随晶粒尺寸的增加而增加，因此对于大尺寸样品，其增强效应变得更加明显，从而导致霍尔-普奇（Hall-Petch）关系成反比。通过控制孪晶薄片的含量来提高透明AlON陶瓷的机械性能是一种潜在有用的方法。