Question

Section-I: Technical terms to research and present your reflections in no more than 10 lines along with a figure/table with proper description, when necessary. Highlight key meaningful term(s) in the write up. (directly copying verbatim answers from the book will carry NO points)

1- Strain hardening and annealing

2- Casting processes for manufacturing components

3- Solid solution and application

Text Book- The Science and Engineering of Materials, Askeland et al. (seven edition)

Answer 1

1:strain hardening : upon cold working (temperature less than 0.4 times of melting temperature) the number of dislocations (line defect) in material increases and these dislocation piles up at the grain boundary and create a dislocation forest. Since dislocation - dislocation interactions are repulsive in nature ,so dislocation forest create back stress in movement of dislocation. This increases the strength of material. Addition of stress gives additional of strain with faster rate in strain hardening region and material undergoes change in its atomic and crystalline structure resulting in increased resistance to further deformation.the figure showing the strain hardening region in the stress strain curve for tension of mild steel is attached.

2:Casting process: casting is a manufacturing process in which molten material is poured into the mould cavity which contains a hollow cavity of the desired shape and then it is allowed to solidify .the mould cavity is first made by pattern which is replica of final product with some allowances.

3:solid solution: solid solution are the solutions in solid state which consist of solute and solvent. In solid solutions the two materials dissolve each other and form a single phase alloy. Two types of solution exist Interstitial solid solution (solute atom size is less than solvent atom) and substitial solid solution (solute atom size is more than solvent atom)