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In materials science, lamellar structures or microstructures are composed of fine, alternating layers of different materials in the form of lamellae. They are often observed in cases where a phase transition front moves quickly, leaving behind two solid products, as in rapid cooling of eutectic (such as solder ) or eutectoid (such as pearlite ...
Lamellae form during crystallization from the melt. The arrow shows the direction of temperature gradient. [5] Nucleation starts with small, nanometer-sized areas, where a result of heat motions in some chains or their segments occur parallel. Those seeds can either dissociate, if thermal motion destroys the molecular order, or grow further, if ...
Commonly, in gaps between the lamellae, a fine-grained mixture of kamacite and taenite called plessite can be found. [1] Widmanstätten structures describe analogous features in modern steels, [2] titanium, and zirconium alloys, but are usually microscopic in size.
Lamellae can also describe the layers of atoms in the crystal lattices of materials such as metals. In surface anatomy, a lamella is a thin plate-like structure, often one amongst many lamellae very close to one another, with open space between. In chemical engineering, the term is used for devices such as filters and heat exchangers.
On the more perfect cleavage, which is parallel to the basal plane (P), is a system of fine striations, parallel to the second cleavage (M). Crystal twinning occurs when two or more adjacent crystals of the same mineral are oriented so that they share some of the same crystal lattice points in a symmetrical manner. The result is an intergrowth ...
Principle of lamellae formation during the crystallization of polymers. Arrow shows the direction of temperature gradient. [1]If a molten linear polymer (such as polyethylene) is cooled down rapidly, then the orientation of its molecules, which are randomly aligned, curved and entangled remain frozen and the solid has disordered structure.
Thylakoid structures Scanning transmission electron microscope (STEM) imaging of thylakoid membranes 10-nm-thick STEM tomographic slice from a lettuce chloroplast. Grana stacks are interconnected by unstacked stromal thylakoids, called stroma lamellae.
Amorphous structures exist between the lamellae. Individual molecules can lead to entanglements between the lamellae and can also be involved in the formation of two (or more) lamellae (chains than called tie molecules). Several lamellae form a superstructure, a spherulite, often with a diameter in the range of 0.05 to 1 mm. [46]