MEE 312 Spring 2017
 
Project 3
Phase Diagrams and Heat Treatment of Steel
Names of Team members:
 
General Instructions:  Please use this document as a template for responding to your questions.  Please include all of the name of all members of your group.  You will have time in class to work on this mini project.
 
For the heat treating laboratory experiment you performed various heat treating processes on a 1018 steel and a 2024 aluminum alloy.  The questions for this mini-project relate to that lab and should be helpful to you in completing the worksheet or writing/editing the lab report.
 
As a reminder the heat treatments that were employed on the steel and aluminum are as follows in Table 1:
 
Table 1:  Heat Treatment Matrix used in Lab
 

Material
Temp (C )
Cooling
Post treatment

1018 Steel
975
In oven
N/A

1018 Steel
975
In air
N/A

1018 Steel
975
In water (quench)
N/A

 
 
 
 

AA 2024
500
quench
oven at 188 C

 
500
quench
air

 
Relevant phase diagrams are provided below, Figure 1-2:
 
 
Figure 1.  Al-Cu Phase diagram
Figure 2.  Fe – C Phase diagram
 
Table 2 contains information that will be useful to you in answering some of the questions on this worksheet (please also note that 1018 steel is very similar to 1020 steel):
 
Table 2. Properties of various Aluminum and Steel Materials
 
 
Additional information that might be helpful in completing this worksheet (from Alloys-supply.com).  Please note that you can also find this information in chapter 14 of your text book.
 
 
 
QUESTION 1
 
Please consider the data provided in Table 2 for the aluminum alloys (AA1060-0, AA1060-H, AA 2024-0, AA 2024-T4).

Compare the AA 1060-0 and AA 1060-H. Do you feel that the trends in properties make sense?  Yes or No.  Please explain why you responded yes or no.  In doing this address each property separately and explain in terms of crystallographic defects (be specific please) and using concepts of slip.

UTS:
Offset yield:

Elongation:

Elastic Modulus:
Hardness:

 

Compare the AA 1060-0 and AA 2024 -0. Do you feel that the trends in properties make sense? Yes or No.  Please explain why you responded yes or no.  In doing this address each property separately and explain in terms of microstructure/crystallographic defects (be specific please) and use concepts of slip.  Please also use the phase diagram (assume a temp of 325 C) to help explain your answer.

UTS:
Offset yield:

Elongation:

Elastic Modulus:
Hardness:

 

Compare the AA 2024-0 and AA 2024-T4. Do you feel that the trends in properties make sense? Yes or No.  Please explain why you responded yes or no.  In doing this address each property separately and explain in terms of microstructure/crystallographic defects (be specific please) and use concepts of slip.  Please also use the phase diagram (assume a temp of 325 C) to help explain your answer.

UTS:
Offset yield:

Elongation:

Elastic Modulus:
Hardness:

 

Explain why the AA 1060 is considered to be “non age hardenable” yet the AA 2024 is considered to be age hardenable. Use the phase diagram to explain your answer.

 

Determine the phases present, composition of those phases and amount of those phases for the AA 1060-0 and  AA 2024-0 at 500 C – show all work!!!:

AA 1060-0:

Phases present:
Composition of each phase:
Amount of each phase:

AA 2024-0:

Phases present:
Composition of each phase:
Amount of each phase:

 

For compositions less than 40 wt % Cu (Figure 1) identify all of the three phase reactions by reaction and name:

 

For equilibrium cooling show the development of the microstructure (using very clear and well labeled figures with text to accompany if needed) for the AA 1060, AA 2024 and a eutectic composition of Al-Cu materials upon cooling from 700 C (it may be helpful to include the phase diagram with this if you feel there is ambiguity about temps and composition):

AA 1060:

700 C
640 C
550 C
400 C

AA 2024:

700 C
640 C
550 C
400 C

Eutectic composition:

700 C
640 C
550 C
400 C

 

For the AA 2024 material, using Table 1 – Explain the steps being employed (name of step, anticipated microstructure) and make some comments as to what you expect the relative hardnesses to be for the sample that was allowed to sit at RT versus the ones that you put back in the oven.

Steps:
“Hardness” hypothesis:

General phase diagram questions:

Figure 1 represents what type of phase diagram (classification)
Show an example of a liquidus, solidus, solvus and “three-phase reaction isotherm” lines on Figure 1.

Do we know for sure that the Hume-Rothery criteria are met for the Al-Cu system, yes or no, explain why you answered this way.

 
 
 
 
 
 
 
 
 
 
 
 
 
 
QUESTION 2
 
Please consider the data provided in Table 2 for the various Steel materials.

Compare the 1020 Steel and the 3120 Steel. Do you feel that the trends in properties make sense?  Yes or No.  Please explain why you responded yes or no.  In doing this address each property separately and explain in terms of microstructure/crystallographic defects (be specific please) and use concepts of slip.

UTS:
Offset yield:

Elongation:

Elastic Modulus:
Hardness:

 

Compare the 1020 steel and the Annealed 1075 steel. Do you feel that the trends in properties make sense? Yes or No.  Please explain why you responded yes or no.  In doing this address each property separately and explain in terms of microstructure/crystallographic defects (be specific please) and use concepts of slip.  Please also use the phase diagram, Figure 2 or another that you locate (assume a temp of 400 C) to help explain your answer.

UTS:
Offset yield:

Elongation:

Elastic Modulus:
Hardness:

 

Compare the AQT 1075 Steel with the Annealed 1075 steel. Do you feel that the trends in properties make sense? Yes or No.  Please explain why you responded yes or no.  In doing this address each property separately and explain in terms of microstructure/crystallographic defects (be specific please) and use concepts of slip.  Please also use the phase diagram, Figure 2 or another that you locate (assume a temp of 400 C) to help explain your answer.

UTS:
Offset yield:

Elongation:

Elastic Modulus:
Hardness:

 

In figure 2 there are three, three-phase reactions identified with colored dots.  Please provide the reaction that is occurring for the names provided:

Peritectic
Eutectic

Eutectoid

 

Show the development of the microstructure of a 1090 steel cooled under equilibrium conditions at the temperatures provided and right next to the figures provided, explain the development for a hypoeutectoid steel (not all temps though – use table to assist you in doing this and you can make the rows fatter to accommodate nice clear pics and you can also use text to explain your figures:

 
 
 
 

Temp (C)
1090 Steel
Hypoeutectoid steel (such as 1018)

1800
 
No response here please

1450
 
No response here please

1000
 
 

725
 
 

400
 
 

 

Determine the composition and amount of phases (not microconstituents) present for a 1090 steel cooled under equilibrium conditions at the temperatures provided:

 

Temp (C)
1090 Steel

1000
 

725
 

400
 

 

Using the information provided in Table 1 for the 1018 steel explain the microstructures (you may accompany explanation with drawings if you would like) and relative hardness you found (or expected to find) for the 1018 steel with three different post treatments (Rows 1-3).

 

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