MSE 220 Fall 2019 - Quiz 2
October 3, 2019
Name: _______Solution___________________________
Discussion 101 102 103 104 105
Honor Pledge (write out):
______________________________________________________________________________
______________________________________________________________________________
Signature: ________________________________
1
, 1. (9 pts) List the three general types of imperfections, or defects, we see in crystalline metals.
Provide an example of each type and describe in words or with pictures what that example looks
like in the crystal.
Point
Vacancy – empty lattice site or host atom missing from lattice point
Substitutional – other atom on lattice site replacing host
Interstitial – atom in one of the spaces between lattice points
Line
Dislocation – extra half plane of atoms
Plane
Grain boundary – the disordered region between two grains where a grain is a region of the
crystal having the same crystal structure, but different orientation from surrounding grains
Surface – the external surface of the crystal – the atoms at this external surface are not bonded
to other atoms in the solid on this surface.
2. (2 pts) You are given an alloy containing 100 g of Cu and 20 g of Zn. Determine the
composition of the alloy in weight percent.
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 100𝑔𝑔
𝑤𝑤𝑤𝑤%𝐶𝐶𝐶𝐶 = 𝑥𝑥100 = 𝑥𝑥100 = 83.33𝑤𝑤𝑤𝑤%𝐶𝐶𝐶𝐶
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 + 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 20𝑔𝑔 + 100𝑔𝑔
Or
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 20𝑔𝑔
𝑤𝑤𝑤𝑤%𝑍𝑍𝑍𝑍 = 𝑥𝑥100 = 𝑥𝑥100 = 16.67𝑤𝑤𝑤𝑤%𝑍𝑍𝑍𝑍
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 + 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 20𝑔𝑔 + 100𝑔𝑔
2
October 3, 2019
Name: _______Solution___________________________
Discussion 101 102 103 104 105
Honor Pledge (write out):
______________________________________________________________________________
______________________________________________________________________________
Signature: ________________________________
1
, 1. (9 pts) List the three general types of imperfections, or defects, we see in crystalline metals.
Provide an example of each type and describe in words or with pictures what that example looks
like in the crystal.
Point
Vacancy – empty lattice site or host atom missing from lattice point
Substitutional – other atom on lattice site replacing host
Interstitial – atom in one of the spaces between lattice points
Line
Dislocation – extra half plane of atoms
Plane
Grain boundary – the disordered region between two grains where a grain is a region of the
crystal having the same crystal structure, but different orientation from surrounding grains
Surface – the external surface of the crystal – the atoms at this external surface are not bonded
to other atoms in the solid on this surface.
2. (2 pts) You are given an alloy containing 100 g of Cu and 20 g of Zn. Determine the
composition of the alloy in weight percent.
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 100𝑔𝑔
𝑤𝑤𝑤𝑤%𝐶𝐶𝐶𝐶 = 𝑥𝑥100 = 𝑥𝑥100 = 83.33𝑤𝑤𝑤𝑤%𝐶𝐶𝐶𝐶
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 + 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 20𝑔𝑔 + 100𝑔𝑔
Or
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 20𝑔𝑔
𝑤𝑤𝑤𝑤%𝑍𝑍𝑍𝑍 = 𝑥𝑥100 = 𝑥𝑥100 = 16.67𝑤𝑤𝑤𝑤%𝑍𝑍𝑍𝑍
𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 + 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 20𝑔𝑔 + 100𝑔𝑔
2
