Why metals are malleable and ductile?Weegy:
In short, metals are malleable and ductile because of the movement of dislocations.
Dislocations are linear defects in crystals where the normal pattern of bonding is not preserved. The concept of a dislocation is much easier to understand with pictures, so I suggest you check out the wikipedia page...
Dislocations move, accommodating deformation, when you apply a stress to the metal. At room temperature, the main parameters controlling the movement of the dislocation are the shear modulus of the crystal and the Pierls stress, which is related to the strength of the bonding in the crystal and the interatomic distance (Pierls stress is also a function of the shear modulus). A lower shear modulus and a lower Pierls stress lead to dislocations that are easier to move. The easier dislocations are to move, the more deformable your crystal is. You can look up the shear modulus on the wikipedia page for any metal. The Pierls stress is a function of temperature; the Pierls stress goes down with increasing temperature. At significantly higher temperature, other processes become important (diffusion, dislocation climb, grain boundary sliding), but I don't think that is what your question is referring to.
Note that I phrased the last paragraph in terms of dislocations in crystals. This means that any crystalline material can be deformed by the movement of dislocations. For instance, salt, ice, or any rock can all be deformed ductilely through the movement of dislocations. The reason metals are ductile at room temperature has to do with their lower shear moduli and lower Pierls stress than most ceramic minerals.Auto Answered|Score 1Weegy:
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