Abnormal grain growth

Abnormal or discontinuous grain growth leads to a heterogeneous microstructure where a limited number of grains grow much faster than the rest.

In materials science, abnormal or discontinuous grain growth, also referred to as exaggerated or secondary recrystallisation grain growth, is a grain growth phenomenon in which certain energetically favorable grains (crystallites) grow rapidly in a matrix of finer grains, resulting in a bimodal distribution of grain size.

In ceramic materials, this phenomenon can result in the formation of elongated prismatic, acicular (needle-like) grains in a densified matrix. This microstructure has the potential to improve fracture toughness by impeding the propagation of cracks.^[1]

^ Padture, N. P.; Lawn, B. R. (1994). "Toughness properties of a silicon carbide with an in situ induced heterogeneous grain structure". J. Am. Ceram. Soc. 77 (10): 2518–2522. doi:10.1111/j.1151-2916.1994.tb04637.x.

[ref3-1] Padture, N. P.; Lawn, B. R. (1994). "Toughness properties of a silicon carbide with an in situ induced heterogeneous grain structure". J. Am. Ceram. Soc. 77 (10): 2518–2522. doi:10.1111/j.1151-2916.1994.tb04637.x.

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