Download - MSE 201 LAB II: Part b
MSE 201 LAB II: Part bMSE 201 LAB II: Part b
Annealing Copper AlloysAnnealing Copper Alloys
Lab OverviewLab Overview
• Each alloy (Pure, 5% Zn, 10% Zn, 20% Zn) will Each alloy (Pure, 5% Zn, 10% Zn, 20% Zn) will be annealed for 45 minutes at 8 be annealed for 45 minutes at 8 temperatures:temperatures:
200°C, 250°C, 300°C, 350°C, 400°C, 500°C, 200°C, 250°C, 300°C, 350°C, 400°C, 500°C, 600°C, and 800°C600°C, and 800°C
• Hardness after each anneal will show amount Hardness after each anneal will show amount of recrystallization or grain growthof recrystallization or grain growth
• PROCEED TO FURNACE ROOM TO CONDUCT PROCEED TO FURNACE ROOM TO CONDUCT ANNEALINGANNEALING
What is Recrystallization?What is Recrystallization?• Recovering damage and forming new grains by Recovering damage and forming new grains by
addition of heataddition of heat
(click to play)
Stages During AnnealingStages During Annealing• I: RecoveryI: Recovery• II: RecrystallizationII: Recrystallization• III: Grain GrowthIII: Grain Growth
Hardness vs. Annealing Temp
25
75
125
175
0 200 400 600 800
Temp, °C
Har
dn
ess,
DP
H 20% Zn
10% Zn
5% Zn
Pure Cu
Goal: Goal: Plot of Hardness vs. Annealing Plot of Hardness vs. Annealing TempTemp
I: Recovery
II: Recrystallization
III: Grain Growth
Joined PlotsJoined PlotsHardness vs. %CW and Annealing TemperatureHardness vs. %CW and Annealing Temperature
25
45
65
85
105
125
145
165
185
0 200 400 600 800
Annealing Temp, C
25
45
65
85
105
125
145
165
185
0 10 20 30 40 50 60
%CW
Hardn
ess,
DPH
http://www.copper.org/resources/properties/microstructure/brasses.html
Stress Free Grain
Grain Boundaries
Etch Pits
Annealing Twins
http://www.copper.org/resources/properties/microstructure/brasses.html
Slip LinesSlip Lines
Deformation BandsDeformation Bands
Distorted GrainsDistorted Grains
New Crystal Formation
Microstructure ExaminationMicrostructure Examination• 5% Zinc samples will be examined5% Zinc samples will be examined• Sample 242: Shows effects of % cold workingSample 242: Shows effects of % cold working• Sample 243: Shows effects of annealing temperature.Sample 243: Shows effects of annealing temperature.
• Look for:Look for:– Grain BoundariesGrain Boundaries– Stress Free GrainsStress Free Grains– Distorted GrainsDistorted Grains– New CrystalsNew Crystals– Deformation Deformation
BandsBands– Slip LinesSlip Lines– Annealing TwinsAnnealing Twins– Etch PitsEtch Pits– ScratchesScratches
After Removing Samples…After Removing Samples…
• Remove oxide scale with sand paperRemove oxide scale with sand paper• Average hardness results for each Average hardness results for each
sample (HRF/HRB) and convert to sample (HRF/HRB) and convert to DPHDPH
• Make sure data sheet is completely Make sure data sheet is completely filled outfilled out
• Place samples in recycle box.Place samples in recycle box.• Turn Data Sheet in to TATurn Data Sheet in to TA
Remember: There is a report DUE NEXT WEEK!Remember: There is a report DUE NEXT WEEK!