April 10, 2018

Macroscopic phenomena, such as fracture, corrosion, and degradation of materials, are associated with various reactions which progress heterogeneously. Thus, material properties are generally determined not by their averaged characteristics but by specific features in heterogeneity (or ‘trigger sites’) of phases, chemical states, etc., where the key reactions that dictate macroscopic properties initiate and propagate.

Here, we introduce a new persistent homology approach for identifying trigger sites and apply it to the heterogeneous reduction of iron ore sinters. Four types of trigger sites, ‘hourglass’- shaped calcium ferrites and ‘island’- shaped iron oxides, were determined to initiate crack formation using only mapping data depicting the heterogeneities of phases and cracks without prior mechanistic information.

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Reference 1

Non-empirical identification of trigger sites in heterogeneous processes using persistent homology
Masao Kimura, Ippei Obayashi, Yasuo Takeichi, Reiko Murao & Yasuaki Hiraoka
Scientific Reports volume 8, Article number: 3553(2018)
https://www.nature.com/articles/s41598-018-21867-z

Reference 2

KEK website (in Japanese)
https://www.kek.jp/ja/newsroom/2018/02/26/1400/