Solid. Imperfection in solids. Examples of Imperfections #2. Examples of Imperfections #1. Solid

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1 Solid Imperfection in solids By Solid State of materials Rigid Strong bonding ionic, van der aals, metal bonding normally has crystal structure Examples of Imperfections # Examples of Imperfections # distortion of planes Imperfection distortion of planes Imperfection Imperfection in solid 3 Imperfection causes distortion of planes and abnormal arrangement of atoms. This affects properties of materials: mechanical, electrical properties and so on. 4

2 an atom # Vacancy an atom # Substitutional Solid Solution This defect called Vacancy This defect called Substitutional Solid Solution (by a bigger atom) 5 6 an atom#3 Substitutional Solid Solution an atom#4 Interstitial Solid Solution Space between atoms This defect also called Substitutional Solid Solution (by a smaller atom) This defect also called Interstitial Solid Solution (by a very small atom) 7 8

3 an atom #5 Summary: defects cause by an atom could be: Vacancy Substitutional solid solution (by bigger or smaller atoms) Interstitial solid solution an atom #7 Amount or number of defect found in crystal can be calculated by Number of defect depends on Temperature. 9 0 an atom #8 Defect causes by an atom has no dimension or zero dimension!! It can be called Point defect. Remember that point defect is a defect causes by an atom (or absence of atom) and it has zero dimension. There are other kinds of defects which have one, two or three dimensions (D, D, 3D). Note that : D has only length () D has length ()*width() 3D has length()*width()*depth(d) D Defect causes by an atom has no dimension or zero dimension!! It can be called Point defect. Imperfection: ine Defect Remember that point defect is a defect causes by an atom (or absence of atom) and it has zero dimension. There are other kinds of defects which have one, two or three dimensions (D, D, 3D). Note that : D has only length () D has length ()*width() 3D has length()*width()*depth(d) D

4 Imperfection- ine defect # Imperfection- ine defect # Extra plane ine defect or Dislocation Perfect crystal Perfect crystal This type of dislocation is called Edge dislocation which can be considered as a line defect. 3 4 Imperfection- ine defect #3 Defect causes by an atom has no dimension or Imperfection: zero dimension!! Interfacial Defect It can be called Point defect. Remember that point defect is a defect causes by an atom (or absence of atom) and it has zero dimension. The Screw dislocation also can be considered as a line defect in materials 5 There are other kinds of defects which have one, two or three dimensions (D, D, 3D). Note that : D has only length () D has length ()*width() 3D has length()*width()*depth(d) D 6

5 Imperfection- Interfacial defect # Imperfection- Interfacial defect # Atom A Planar Defect Planar Defect Atom B Planar defect or Interfacial defect is a two-dimensions defect such as interface between two materials, grain boundary and so on. 7 8 Defect causes by an atom has no dimension or zero Imperfection: dimension!! Bulk Defect It can be called Point defect. Remember that point defect is a defect causes by an atom (or absence of atom) and it has zero dimension. There are other kinds of defects which have one, two or three dimensions (D, D, 3D). Note that : D has only length () D has length ()*width() 3D has length()*width()*depth(d) D 9 H Imperfection- Bulk defect # Perfect crystal Imperfection or Defect occurs Defect is a threedimensions defect (it has height, width and length). Bulk defects can be impurities, hole, crack which have threedimensions. 0

6 Summary about imperfections properties # Interfacial defects Crack, Holes, Impurities Bulk defects properties # properties #3 3 4

7 Slip occurs in these plane properties #4 properties #5 5 6 properties #6 properties #7 Need low force Need higher force ow dislocation density Deform easily High dislocation density Deform hardly 7 8

8 Summary of Dislocation VS Mechanical properties Calculation of concentration 9 30 Calculation of concentration Other useful relations Concentration in mass per unit volume (kg/m 3 ) Average density (kg/m 3 ) Average atomic weight " C C + ρ ρ ρ 3 0 C C ave 00 C C + ρ ρ Note that:. these equations can be used for two element alloy. A ave C + " C C + ρ ρ 3 0 C C. C is concentration by weight (weight percent), C is concentration by atom(atomic percent) C A A ρ ave C' A + C' A C' A C' A + ρ ρ C A + C' A ave 00 ' A Example in concentration calculation Al 94 g+ Cu 6 g Calculate weight percent of Al and Cu Calculate atomic percent of Al and Cu Calculate concentration by mass per unit volume Calculate average density Calculate average atomic weight 3

9 Optical Microscope # Optical Microscope # 33 34