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“爆炸”和“流泪”陶瓷
作者:小柯机器人 发布时间:2021/11/20 21:56:47

美国明尼苏达大学James, Richard D.团队报道了爆炸和“流泪”陶瓷。相关研究成果于2021年11月17日发表在《自然》。

系统调节晶格参数以改善不同相之间的运动兼容性,是改善固相-固相转变可逆性和降低滞后性的一种广泛有效的策略(运动相容性是指相位的配合)。

该文中,研究人员给出了一个明显矛盾的例子,在这个例子中,调整到接近完美的运动相容性会导致异常高的不可逆性。具体而言,当通过四方相到单斜相转变冷却运动相容陶瓷(Zr/Hf)O2(YNb)O4时,多晶在其晶界处缓慢而稳定地崩解(研究人员称之为“流泪”过程),甚至爆炸性崩解。相反,如果我们调整晶格参数以满足更强的“等距离”条件(考虑了样品形状),则产生的材料表现出低滞后的可逆行为。

以上结果表明,在化学均质陶瓷系统中,通过以意想不到的方式操纵相容性条件,可以实现从一个极端可逆到另一个极端爆炸的多种行为。该概念可能在目前寻找形状记忆氧化物陶瓷的过程中至关重要。

附:英文原文

Title: Exploding and weeping ceramics

Author: Gu, Hanlin, Rohmer, Jascha, Jetter, Justin, Lotnyk, Andriy, Kienle, Lorenz, Quandt, Eckhard, James, Richard D.

Issue&Volume: 2021-11-17

Abstract: 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.

DOI: 10.1038/s41586-021-03975-5

Source: https://www.nature.com/articles/s41586-021-03975-5

 

期刊信息

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:42.778
官方网址:http://www.nature.com/