Atomic arrangement of materials 0.0 / 5 ? EngineeringMicro-structure of materialsUniversityNone Created by: OmololaS15Created on: 21-12-18 11:33 Give some properties of Ceramics Strong in compression, wear resistant, Brittle, low resistance to crack propagation 1 of 14 Give some properties of metals Ductile, Tough,easily oxidised, melt at moderate temperatures 2 of 14 Give some properties of Polymers low density, low modulus value,Thermoplastics vs thermosetting 3 of 14 What is a composite? A mixture of materials to create one new material. 4 of 14 Define lattice An array of points such that each point has an identical environment. 5 of 14 Define motif A group of atoms (molecule included) 6 of 14 How is Crystal Structure created? Lattice +Motif --> Crystal Structure 7 of 14 What are the two main atomic arrangements of metals and how are they chosen? Hexagonal (close packed), Square (not close packed); The arrangement that gives the material the least free Gibbs energy is chosen. 8 of 14 Give examples of the hexagonal arrangement Close packed hexagonal- ABAB (Zn,Mg,Ti); Face centred cubic- ABCABC (Cu,Al,Pb) 9 of 14 Give examples of the square arrangement Body centred cubic - the 2nd layer is placed in between the 1st layer of atoms and the 3rd after that. 10 of 14 What do intrinsic defects depend on? The number of defects depend temperature. 11 of 14 Explain what we mean by a 'vacancy' Vacancy; the absence of an atom which produces an inward stress and are responsible for atomic diffusion 12 of 14 What is an interstitial defect/impurity? When a smaller atom is placed in the gaps between the other atoms 13 of 14 What is an substitutional defect/impurity? larger atoms in place of smaller ones (local stress outwards) 14 of 14
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