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Exploding and weeping ceramics
Nature ( IF 64.8 ) Pub Date : 2021-11-17 , DOI: 10.1038/s41586-021-03975-5
Hanlin Gu 1 , Jascha Rohmer 2 , Justin Jetter 2 , Andriy Lotnyk 3, 4 , Lorenz Kienle 2 , Eckhard Quandt 2 , Richard D James 1
Affiliation  

The systematic tuning of crystal lattice parameters to achieve improved kinematic compatibility between different phases is a broadly effective strategy for improving the reversibility, and lowering the hysteresis, of solid–solid phase transformations1,2,3,4,5,6,7,8,9,10,11. (Kinematic compatibility refers to the fitting together of the phases.) Here we present an apparently paradoxical example in which tuning to near perfect kinematic compatibility results in an unusually high degree of irreversibility. Specifically, when cooling the kinematically compatible ceramic (Zr/Hf)O2(YNb)O4 through its tetragonal-to-monoclinic phase transformation, the polycrystal slowly and steadily falls apart at its grain boundaries (a process we term weeping) or even explosively disintegrates. If instead we tune the lattice parameters to satisfy a stronger ‘equidistance’ condition (which additionally takes into account sample shape), the resulting material exhibits reversible behaviour with low hysteresis. These results show that a diversity of behaviours—from reversible at one extreme to explosive at the other—is possible in a chemically homogeneous ceramic system by manipulating conditions of compatibility in unexpected ways. These concepts could prove critical in the current search for a shape-memory oxide ceramic9,10,11,12.



中文翻译:

爆炸和哭泣的陶瓷

系统调整晶格参数以提高不同相之间的运动相容性是一种广泛有效的策略,可提高固-固相变的可逆性和降低滞后1,2,3,4,5,6,7, 8,9,10,11。(运动相容性是指相位的拟合。)这里我们提出了一个明显自相矛盾的例子,其中调整到接近完美的运动相容性会导致异常高度的不可逆性。具体来说,当冷却运动相容性陶瓷 (Zr/Hf)O 2 (YNb)O 4通过其四方到单斜的相变,多晶在其晶界处缓慢而稳定地分崩离析(我们称之为渗出的过程),甚至爆炸性地分解。相反,如果我们调整晶格参数以满足更强的“等距”条件(这还考虑了样品形状),则所得材料表现出低滞后的可逆行为。这些结果表明,通过以意想不到的方式操纵相容性条件,在化学均质的陶瓷系统中,可以实现多种行为——从一个极端的可逆到另一个极端的爆炸性。这些概念在当前寻找形状记忆氧化物陶瓷9,10,11,12中可能被证明是至关重要的。

更新日期:2021-11-17
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