1. (a) What is the difference between crystal structure and crystal system? Consider a face-centered cubic (FCC) crystal
Posted: Sat Feb 26, 2022 11:54 am
1. (a) What is the difference between crystal structure and
crystal system? Consider a face-centered cubic (FCC) crystal
structure that has a unit cell length a and the atomic radius
R.
(i) Show that for FCC, 4R = a√2.
(ii) Calculate the number of atom in a cell unit of FCC.
(iii) Calculate the atomic packing factor. (12 marks)
(b) What is meant by plastic deformation and elastic deformation
of materials? Sketch qualitative stress–strain curves for ceramics,
metals and polymers. Describe your sketch for each material.(8
marks)
crystal system? Consider a face-centered cubic (FCC) crystal
structure that has a unit cell length a and the atomic radius
R.
(i) Show that for FCC, 4R = a√2.
(ii) Calculate the number of atom in a cell unit of FCC.
(iii) Calculate the atomic packing factor. (12 marks)
(b) What is meant by plastic deformation and elastic deformation
of materials? Sketch qualitative stress–strain curves for ceramics,
metals and polymers. Describe your sketch for each material.(8
marks)