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

A. Recrystallization

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?

C. Zinc

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

D. Intergranular propagation

QUESTION 4
The formation of Titanium Oxide on the surface of your shiny new bicycle frame reduces corrosion by:

A. Passivation

QUESTION 5
 A slip system is made up of:

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

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?

B. Aluminum

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?

B. Between 0.1 and 0.01 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

False

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

True

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

D. 1,4,3,2

Question 12

All of the following are reasons why dislocation movement is generally easier in metals than ceramics EXCEPT.

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

QUESTION 13
A ductile to brittle transition temperature is most likely to be observed in which materials:

D. All metals

QUESTION 14
 During cold working, all the following happen EXCEPT:

E. the recrystallization temperature changes

Question 15

A substitution soils solution is made by alloying element A and element B together   

D. Evenly distribute throughout the material

Question 16

Which metal bar will have the highest creep rate?

B. A bar at 600 degree Celsius and under a stree of 40 MPa

Question 17

Match the correct answer with each statement

Option A perpendicular to each other

Option A perpendicular to each other

Option B Same direction for both

Option B Same direction for both

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

Pitting corrosion is a localized form of corrosion by which cavities or "holes" are produced in the material. Pitting is considered to be more dangerous than uniform corrosion damage because it is more difficult to detect, predict and design against. Corrosion products often cover the pits

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

In materials science, fracture toughness is the critical stress intensity factor of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited

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.

Normalizing process :

It is same as annealing but material cooled fats and open atmosphere along with the grana and it becomes fine and uniform which is also an impact on material softness

b)     Once the machining is complete, briefly describe a possible process you could use to increase the surface hardness of the part.

Flame hardening:

The surface of material which is heated and austenic temperature and cooled through water that forms martensite on surface along hardness increase.

Carbonitriding and Cyaniding

Both nitrogen and carbon is interested don surface

Question 2 1

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

·         Mechanical failure

In this picture 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 fatigue failures;

·         Observe and redesign product surface 

·         Surface Carburization technique

Question 23

Please upload a response to following question

For response 1:

Free response 2: Victor Viking has lost his metal shield in the blusterous northern ocean.

Free response 2: