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Segregation is one of defect in the casting process result of separation of impurities and alloying elements in different casting regions (different composition)Micro segregation occurs over distances comparable to the size of the dendrite arm spacing. This occurs as a result of the first solid formed being of a lower concentration than the final equilibrium concentration, resulting in partitioning of the excess solute into the liquid, so that solid formed later has a higher concentrationMacro segregation occurs over similar distances to the size of the casting. This can be caused by a number of complex processes involving shrinkage effects as the casting solidifies, and a variation in the density of the liquid as solute is partitionedIs it feasible? Micro segregation can be removed by annealing at high temperatures where diffusivity is higher. Distances (typically on the order of 10 to 100 m) are sufficiently small for diffusion to be a significant mechanism). But macro segregation cannot because occur larger distances, but can be reduced buy control casting process and mixing during solidification.

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Annealing twin is the result of a change in crystal system during heat treatment as one form becomes unstable and the crystal structure must reorganize or transform into another another more stable formDeformation twin is the result of stress on the crystal after the crystal has formed.

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dP/dT is mostly positive.

A phase transition consists of three state of matter: liquid, solid and gas. The lines represent the combinations of pressures and temperatures at which two phases can exist in equilibrium. In other words, these lines define phase change points.

Triple point the point on a phase diagram at which the three states of matter: gas, liquid, and solid coexistCritical point the point on a phase diagram at which the substance is indistinguishable between liquid and gaseous statesThe red line divides the solid and gas phases, represents sublimation (solid to gas) and deposition (gas to solid). The green line divides the solid and liquid phases and represents melting (solid to liquid) and freezing (liquid to solid). The blue divides the liquid and gas phases, represents vaporization (liquid to gas) and condensation (gas to liquid)

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b)Diffusion is material transport by atomic motion, interdiffusion occurs in response to a concentration gradient resulting inhomogenous materials can become homogeneous. For an active diffusion to occur, the temperature should be high enough to overcome energy barrier to atomic motion. 11

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A fivefold axis of symmetry cannot exist in a periodic lattice, since it is impossible to fill the area of a plane with a connected array of pentagons. However, we can fill the area of a plane with two distinct designs. A crystal constructed from a non-random assembly of two unique designs is called a quasicrystal. Mathematicians have shown that it is impossible to construct such a pattern from a single base pattern13

Are very weak against impact because a slight shock may produce fracture even when the material itself is ductile under static loading.14

Drive in

Concentration (cm-3)

Without Drive inDepth (micro m)

Yellow line as implanted, green line: drive in -> dopant diffuse inside. Drive in or annealing make boron is driven deeper into the wafer.15

1. Coalescence between two sub grain by rotation of one of them :

2. Coalescene collisionCoalescence sintering occurs when two cluster touch or collide and merge to form a bigger cluster

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Phase determination can be performed by a comparison of a set of experimental d spacing and known d spacing from data base. The d-spacing of each peak is then obtained by solution of the Bragg equation for the appropriate value of . Once all d-spacings have been determined, automated search/match routines compare the ds of the unknown to those of known materials. Because each mineral has a unique set of d-spacings, matching these d-spacings provides an identification of the unknown sample. A systematic procedure is used by ordering the d-spacings in terms of their intensity beginning with the most intense peak