The spaghetti incident

Throughout their use, materials are exposed to mechanical stress, which deforms and damages them. Such stress can be both mechanical, like an unforeseen impact, and thermal, such as a temperature change. This causes the formation and propagation of numerous defects within the material. However, the only way to understand, and therefore predict, their collective behaviour is to use numerical simulations. This micrometre-scale image, produced by digital modelling, shows a sample of copper that has cracked. A microstructure of dislocations – linear defects that cause plastic deformation, here seen resembling tangled spaghetti – was formed by the opening of the crack. This type of modelling can be applied to any crystalline material, and in particular to the metal alloys used in aircraft engines, as well as the semiconductors found in most electronic devices. This image is a winner of the 2021 La preuve par l'image (LPPI) competition.