Category: Material Science and Engineering

Mechanical Properties of Metals

6) Mechanical Properties of Metals 1. Introduction Often materials are subject to forces (loads) when they are used. Mechanical engineers calculate those forces and material scientists how materials deform (elongate, compress, twist) or break as a function of applied load, time, temperature, and other conditions.Materials scientists learn about these mechanical properties by testing materials. Results…

By Sdbamie 28 April 2020 Off

Diffusion In Solids

5) Diffusion in solids 5.1 Introduction Many important reactions and processes in materials occur by the motion of atoms in the solid (transport), which happens by diffusion. In homogeneous materials can become homogeneous by diffusion, if the temperature is high enough (temperature is needed to overcome energy barriers to atomic motion. 5.2 Diffusion Mechanisms Atom…

By Sdbamie 28 April 2020 Off

Defects in Solids

4) Defects(Imperfections) in Solids   Imperfections in Solids 4.1 Introduction Materials are often stronger when they have defects. The study of defects is divided according to their dimension: 0D (zero dimension) – point defects: vacancies and interstitials. Impurities. 1D – linear defects: dislocations (edge, screw, mixed) 2D – grain boundaries, surfaces. 3D – extended defects:…

By Sdbamie 28 April 2020 Off

STRUCTURE OF CRYSTALS

3) STRUCTURE OF CRYSTALS 3.2 Fundamental Concepts Atoms self-organize in crystals, most of the time. The crystalline lattice, is a periodic array of the atoms. When the solid is not crystalline, it is called amorphous. Examples of crystalline solids are metals, diamond and other precious stones, ice, graphite. Examples of amorphous solids are glass, amorphous…

By Sdbamie 28 April 2020 Off

ATOMIC STRUCTURE AND BONDING

2) ATOMIC STRUCTURE AND BONDING 2.2 Fundamental Concepts Atoms are composed of electrons, protons, and neutrons. Electron and protons are negative and positive charges of the same magnitude, 1.6 × 10^19 Coulombs.The mass of the electron is negligible with respect to those of the proton and the neutron, which form the nucleus of the atom.…

By Sdbamie 28 April 2020 Off