Which of the following processes generally results in the most dramatic changes in strength and ductility?

A. Recrystallization

B. Dislocation annihilation

C. Recovery

 D.Grain growth

QUESTION 2
Which of the following coating choices would provide the best sacrificial galvanic corrosion protection for a Nickel base metal if the coating was damaged?

A. Copper

B. Iron

C. Zinc

D. Titanium

QUESTION 3
 Which of the following is NOT a strengthening mechanism for a metal alloy?

A. Reducing grain size

 B. Solid solution strengthening

C. Cold work

D. Intergranular propagation
QUESTION 4
The formation of Titanium Oxide on the surface of your shiny new bicycle frame reduces corrosion by:
A. Passivation

 B. forming a sacrificial anode

 C. reflecting UV rays that contribute to corrosion

D. it doesn't reduce corrosion, it makes it worse!

QUESTION 5
 A slip system is made up of:

A. An edge and/or screw dislocation and a shear stress

B. A slip plane and resolved shear stress

C. A failure surface and plastic deformation

D. A slip plane and slip direction
QUESTION 6
 A 10 mm diameter cylindrical rod fabricated from 1045 steel (see figure below) is subjected to reversed tension-compression load cycling along its axis. If the maximum tensile and compressive loads are +23,500 N and -23,500 N respectively, determine its fatigue life. The stress plotted in the figure below is stress amplitude. 1045 steel Stress amplitude, S (MPa) Stress amplitude (10 psi) 2014-T6 aluminum alloy Red brass 103 104 105 108 109 1010 106 107 Cycles to failure, N

A. 100,000 cycles

 B. 150,000

C. 500,000

D. 1,000,000

E. infinite 
QUESTION 7
 You are choosing a material for bolts to secure two copper plates. What bolt material would cause the slowest galvanic corrosion rate?

A. Carbon steel

B. Aluminum

C. Platinum

D. Nickel

QUESTION 8
The Hall-Petch parameters 0=25 MPa and ky=12.5 MPa (mm)" have been determined for a particular alloy. What average grain size diameter is needed to obtain a yield strength of 100 MPa?
A. >0.1 mm
B. Between 0.1 and 0.01 mm

C. Between 0.01 mm and 0.001 mm

D. <0.001 mm
QUESTION 9
A very small fiber of a ceramic is more likely to have higher failure strength than a large piece of the same ceramic
True

False

QUESTION 10
Dislocation motion is the mechanism for creep behavior of ductile materials

True

False
Question 11
A metal alloy is cold rolled and then annealed. Order the micrograph in time sequences from first to last

A. 1,2,3,4

 B. 1,3,2,4

 C. 1,4,2,3

 D. 1,4,3,2
Question 12
All of the following are reasons why dislocation movement is generally easier in metals than ceramics EXCEPT.

A. the higher number of slip planes in metals

B. The non-directional nature of metallic bonding

C. the ability of a metal to strain harden when undergoing deformation

 D. The tendency of metals to have close-packed planes

QUESTION 13
A ductile to brittle transition temperature is most likely to be observed in which materials:
A. FCC or HCP metals

B. BCC metals

C. Ceramics

D. All metals
QUESTION 14
 During cold working, all the following happen EXCEPT:

A. Dislocation density increases

 B. yield strength increases

C. tensile strength increases

D. ductility increases

E. the recrystallization temperature changes
Question 15
A substitution soils solution is made by alloying element A and element B together   
Option B is correct
Question 16
Which metal bar will have the highest creep rate?
Option C is correct
Question 17
Match the correct answer with each statement
Option A perpendicular to each other (The motion of edge dislocation line and the direction of the applied shear stress)
Option A perpendicular to each other (The motion of an screw dislocation line and the direction of the applied shear stress)
Option B Same direction for Both ( The direction of an plastic deformation for an edge dislocation and the direction of the applied shear stress)
Option B Same direction for Both ( The direction of an plastic deformation for an screw dislocation and the direction of the applied shear stress)
Question 18
A not so brilliant orthodontist decided to make braces out of 1060 steel and attach them to his patient teeth. Describe two types of corrosion that are likely occurring in the braces and the reason you think so (1 sentence for each type of corrosion and reasoning).
Answer
Pitting Corrosion

The pitting corrosion is the localized form of the corrosion that is either local anodic point or more commonly a cathode point, forms a small corrosion cell with the surrounding normal surface. Once a pit is initiated, it grows into a hole or cavity.

Cercise corrosions

It is also the local form of corrosion as well as usually the result from a stagnant microenvironment in which there are differences in the concentration of ions between two areas of metal. It occurs in shield area under washers belt heads, gaskets etc.

Question 19
Defile the following three terms;
Strain hardening

Strain hardening is the process of making a metal harder and stronger through plastic deformation. When a metal is plastically deformed, dislocations move and additional dislocations are generated. The more dislocations within a material, the more they will interact and become pinned or tangled.

Recovery

It is just metal springing back elasticity when the load is released. It is generally takes places in the elastic region of stress strain curve.

Fracture toughness

It is the quantitative method of expressing the material resistances to brittle fracture when the crack is presents.

QUESTION 20
Answer the following:
a)      At your work you have a machine that uses a forged (cold-worked) steel part that is exceptionally strong and hard. You want to modify the part by machining it. Describe a possible heat treatment approach that you could use to soften the part for machining.

Cold worked steel part is very hard that is why its machining is very difficult;

Tempering: Heating the component to very temperature then cooled in atmosphere this way removes internal stresses and induced softness. In this process grain structure does not change.

Annealing: The heating component above recrystallization temperature and slowly cooled in furnace. This process is grain structure and its becomes uniform and course in size. It induces the ductility in material and the machining becomes easy.

b)     Once the machining is complete, briefly describe a possible process you could use to increase the surface hardness of the part.
Nitridinging Process: Nitrogen is the interested of surface which is increase hardness of surface.

Induction hardening: From the amount control of current the material surface which is heated as well as cooled through water and oil that is also increase the hardiness of surface along with the thickness of heating is controlled by frequency of current.  

Question 2 1
Explain what type of failure has mostly likely occurred in the picture and how you know

It is mechanical failure which you could also see the clear picture, and where the surface is ribbed or grinded through the leaving of grooves.

Question 22

One of the products your company produced is prone to fatigue failure

There are two possible changes that company produced for the fatigue failure;

·         Surface Carburization technique

·         Observe and redesign product surface  

Question 23

Please upload a response to following question

For response 1: