Libisemisplaane

Libisemisplaane, or slip planes, are crystallographic planes along which dislocations glide during plastic deformation in crystalline materials. They represent preferred pathways for dislocation motion under applied shear stress, with the ease of deformation determined by the atomic packing of the plane.

A slip system consists of a slip plane and a slip direction. Deformation occurs when the resolved shear stress on a slip system exceeds the material’s critical resolved shear stress. Materials tend to deform most readily along their most densely packed planes and directions, which define their dominant slip systems.

In common crystal structures, the active slip planes are:

- Face-centered cubic (FCC): slip on {111} planes in <110> directions; high ductility.

- Body-centered cubic (BCC): slip on {110}, {112}, and sometimes {123} planes with <111> directions; activity varies with temperature.

- Hexagonal close-packed (HCP): basal slip on {0001} planes with <11-20> directions; additional prismatic or pyramidal systems may operate at higher temperatures or in specific alloys.

Slip planes and their associated slip directions determine ductility, work hardening, and mechanical anisotropy. Factors such as temperature, strain rate, impurities, grain size, and pre-existing defects influence which slip systems activate and how easily dislocations move. At low temperatures or in brittle materials, slip can be restricted, leading to brittle fracture; at higher temperatures or in suitably alloyed materials, multiple slip systems can operate, enabling substantial plastic deformation.

Understanding libisemisplaane is essential for crystal plasticity, materials design, and metal forming, where predicting active slip planes helps guide alloy selection and processing strategies.