FYI:
Annealing, in
metallurgy and
materials science, is a
heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. It is a process that produces equilibrium conditions by heating and maintaining at a suitable temperature, and then cooling very slowly. It is used to induce softness, relieve internal stresses, refine the structure and improve cold working properties. There are three stages in the annealing process, with the first being the
recovery phase, which results in softening of the
metal through removal of
crystal defects and the internal stresses which they cause. The second phase is
recrystallization, where new grains nucleate and grow to replace those deformed by internal stresses. If annealing is allowed to continue once recrystallization has been completed,
grain growth will occur, in which the microstructure starts to coarsen and may cause the metal to have less than satisfactory mechanical properties.
The high temperature of annealing may result in oxidation of the metal"™s surface, resulting in scale. If scale is to be avoided, annealing is carried out in an oxygen, carbon, and nitrogen free atmosphere (to avoid oxidation, carburization, and nitriding respectively) such as endothermic g
Annealing, in
metallurgy and
materials science, is a
heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. It is a process that produces equilibrium conditions by heating and maintaining at a suitable temperature, and then cooling very slowly. It is used to induce softness, relieve internal stresses, refine the structure and improve cold working properties. There are three stages in the annealing process, with the first being the
recovery phase, which results in softening of the
metal through removal of
crystal defects and the internal stresses which they cause. The second phase is
recrystallization, where new grains nucleate and grow to replace those deformed by internal stresses. If annealing is allowed to continue once recrystallization has been completed,
grain growth will occur, in which the microstructure starts to coarsen and may cause the metal to have less than satisfactory mechanical properties.
The high temperature of annealing may result in oxidation of the metal"™s surface, resulting in scale. If scale is to be avoided, annealing is carried out in an oxygen, carbon, and nitrogen free atmosphere (to avoid oxidation, carburization, and nitriding respectively) such as endothermic gas (a mixture of carbon monoxide, hydrogen gas, and nitrogen).
In the
semiconductor industry,
silicon wafers are annealed, so that
dopant atoms, usually
boron,
phosphorus or
arsenic, can be incorporated into substitutional positions in the crystal lattice, resulting in drastic changes in the
electrical properties of the semiconducting material.
In the cases of
copper,
steel, and
brass this process is performed by substantially heating the material (generally until glowing) for an extended period of time and allowing it to cool slowly. In this fashion the metal is softened and prepared for further work such as shaping, stamping, or forming.
The
magnetic properties of
mu-metal are introduced as (a mixture of carbon monoxide, hydrogen gas, and nitrogen).
In the
semiconductor industry,
silicon wafers are annealed, so that
dopant atoms, usually
boron,
phosphorus or
arsenic, can be incorporated into substitutional positions in the crystal lattice, resulting in drastic changes in the
electrical properties of the semiconducting material.
In the cases of
copper,
steel, and
brass this process is performed by substantially heating the material (generally until glowing) for an extended period of time and allowing it to cool slowly. In this fashion the metal is softened and prepared for further work such as shaping, stamping, or forming.
annealing
