3. The thermodynamic equation for homogeneous nucleation of a solid from a liquid (i.e. for solidification) is given by: G=4/3r3Gv+4r2s34r3isthevolumeofchuster Explain all the terms in this equation. GV : Dhiving force s: Intarfoinal eneryy Using the above equation, demonstrate either graphically that there is an energy barrier for nucleation. Explain the thermodynamic basis for the use of grain refiner to obtain fine grain size. (a) Briefly describe the benefit of obtaining mechanistic understanding about the connection between microstructure, processing and properties of a material. (b) Different classes of materials can have very different properties, which influence how they are processed, visualised and used. (i) Draw a fully labelled sketch to compare the response of a metal and a ceramic to a tensile load. (ii) Explain the importance of glass transition temperature for the processing and use of polymers. (c) In metallic alloy fabrication, grain refiners are often employed in order to obtain fine grain size during solidification. Explain the thermodynamic basis for the use of a grain refiner