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.
Typically, this results
in softening of the
metal through
removal of
crystal defects and
the internal stresses
which they cause. 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
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