Crystalline Structures :
Many substances, including metals, have a crystalline structure in the solid
state. Metal crystals from when the molten metals cools and solidifies, where
as crystals of other substances, for example copper sulphate, and sodium
chloride ( salt ), form when a saturated solution of compound evaporates
causing the solid to crystallize out.
In crystalline structure , the atoms are located at regular and recurring
positions in three dimension . The pattern may be replicated millions of times
within a given crystal. The structure can be viewed in the form of a unit cell,
which is the basic geometric grouping of atoms that is repeated. There are
several types of pattern in which metallic atoms can arrange themselves on
solidification , but the most common is as
follows :-
1. Body-Centered-Cubic [BCC]
As shown in figure, This structure can be seen as a gathering of cubes with
atoms at the edges and an atom in the center of every cube. The corner or edge
atoms are shared among 8 unit cells .type :Chromium, Molybdenum, Niobium,
Tungsten, Iron.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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