1. Line Defects And Ductility Ductility in a crystalline structure - the amount of plastic deformation it can undergo without fracturing - is affected by line defects in the atomic structure of the crystal. The atoms are arranged in a uniform structure before stress is applied.

2. Line Defects And Ductility When shear stress is applied to the structure, it causes a slip between the planes of the atoms: One row of atoms slips across the other, as shown above.

3. Line Defects And Ductility The substance is crystalline, so ionically bonded. Because of this, only a small amount of energy is required to cause this slip. If a line defect is present, the amount of energy is even less, so a slip is more likely. i.e. materials with the defects are more ductile.

4. Dying, damn you!

5. Ionic Bonds: A Brief Explanation Many of the crystalline substances we are looking at are ionically bonded. This means, basically, that they have either a positive or negative charge. In these ionic substances, there is usually a single electron in the outer shell, which, when solid, is DELOCALISED. This means that it is not stuck in a fixed orbit, and is free to move around the nucleus of the atom randomly. This makes it easier for the electron to bond with other atoms around it, the electron swinging around between the atoms. Because of this, the bonds in the crystalline substance are not strong, little energy is required to break and make the bonds, making it easy for slip to occur.

6. Line Defects And Ductility More often than not, the slip does not move simultaneously, as previously shown. Instead, it moves as illustrated in the following four slides, parts of the structure being pushed across in parts. This can be compared to pushing a carpet across the floor in parts, making a lump in it which is then pushed along the floor in order to move the carpet more easily.

7. Line Defects And Ductility First, the structure of the material is solid, though a line defect is location across the centre. The ionic bonds are held.

8. Line Defects And Ductility When put under a shear force, the atoms on the top and bottom begin to slip past each-other, but gradually, not all at once. The ionic bonds begin to break as the atoms slip, and new ones are formed with the next atom that is met.

9. Line Defects And Ductility As the force continues, the atoms slip further, to a greater degree. More bonds are broken, and more are formed. As the force becomes less, more bonds are formed than broken.

10. Line Defects And Ductility When the force is removed, the atoms have been displaced, and have slipped past each-other into a fairly uniform arrangement with ionic bonds. On a larger scale, the material has been deformed, and this is its new shape.

11. Lien Defects And Ductility This property of the material is useful in many industrial processes, and can alter the shapes of materials for many purposes. However, if a very ductile substance was also needed to be put under further forces then it would be unsuitable. Strength can also be altered using line defects.