1 a True or False The yield strength of a material generally

1. a) True or False? The yield strength of a material generally increases with the square of the dislocation concentration.

b) For the dislocation shown here, in which direction does the Burger\'s vector point? +x, -x, +y, -y?

c) How many slip directions are in just (101) slip plane of a BCC metal?

d) If you wanted to design a metal rod that could hold more weight without permanently deforming, you should:

A. Shot peen the surface.

B. Anneal the rod to remove dislocations.

C. Re-cast the rod from a melt and mix in ceramic powder during solidification.

D. Re-cast the rod from a melt, but this time make it with a smaller diameter.

E. Re-cast the rod from a melt, but this time cool slowly so that you get a larger grain size.

e) True or False? The (101) and (-101) are unique slip planes in a BCC metal.

f)

g) Assuming all have the same grain size and dislocation density, which of these elemental metals would you expect to have the highest yield strength?

A. Not enough information

B. Nickel

C. Iron

D. Cobalt

h)

Solution

a) false

it is directly proportional to dislocation concentration

b) +Y

c) 6

d) a Shot peen