What structural features arrest cracks in stony corals? A high-energy in situ microindentation-microtomography study

Non-metallic, inorganic large brittle structures are not usually interesting for their (rather poor) mechanical properties, however in nature, corals create large mineral structures that are impressively resilient against cyclic wave and tide forces. But how do coral features: struts, polyps, density and phase achieve this? We propose an in situ study in OD19 combining mechanical microindentation with high-energy radiography and tomography, to reveal interactions between indenter, microstructure and cracks, to reveal how the structure resists damage propagation. We will reveal how corals resist cracking and we will explore the interplay between porosity, shape and variable density domains in the struts and corralites. With this we hope to reveal motifs and principles of crack stopping, inspired by the coral system.

非金属无机大型脆性结构通常因力学性能欠佳而较少受到学界关注，但自然界中的珊瑚却能形成大型矿物结构，其对抗周期性波浪与潮汐作用力的韧性令人印象深刻。那么，珊瑚的支柱结构、珊瑚虫、密度与物相等特征是如何实现这一优异性能的？我们提出在OD19开展一项原位研究，将力学微压痕技术与高能射线成像、断层扫描相结合，以揭示压头、微观结构与裂纹之间的相互作用，阐明该结构抵御损伤扩展的内在机制。我们将明确珊瑚抵御裂纹萌生与扩展的原理，并探究支柱与珊瑚萼内孔隙率、形态与可变密度区域之间的相互作用。借此，我们有望揭示受珊瑚系统启发的止裂模式与核心原理。