material science
lansoem.workmz
q11.docLab Report
Microstructures of Pb Sn alloy at different compositions
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Table 1 for Temperature (Show lines on graph) Alloy (Pb/Sn) Start Peak Final 80/20 60/40 40/60 20/80
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Table 2 for equilibrium mass fraction of each phase (Show calculations) |
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Alloy (Pb/Sn) |
Alpha-Phase |
Beta-Phase |
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80/20 |
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60/40 |
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40/60 |
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20/80 |
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From the resultant DSC curves (4 curves are given in the handout) determine the following parameters:
1. Fill in table-1 by determining the initial melting temperature, melting peak for each sample, and final melting point for each sample.
2. Plot the measured transition temperatures (initial and final) on the Pb-Sn phase diagram. Discuss about your observations on that.
3. Estimate the mass fractions of each phase in the composition given below using the lever rule (Use any temperature below 1000C). Fill in table-2 using the values of phase fractions.
4. Calculate the heat of fusion, which is the area under the curve between the solid and the dotted lines for each sample.
5. For each alloy, estimate the mass fractions of each phase from the microstructure given above.
me 215-55 Pb40, 09.05.2005 15:24:31
me 215-55 Pb40, 0.0000 mg
mW
20
°C
150
160
170
180
190
200
210
220
230
240
^exo
SW 8.10
e
R
TA
S
Lab: METTLER
me 215-60 Pb80 Sn20, 08.05.2005 10:14:04
me 215-60 Pb80 Sn20, 0.0000 mg
mW
2
°C
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
^exo
SW 8.10
e
R
TA
S
Lab: METTLER
Pb-Sn phase diagram
(80%Pb-20%Sn)
(40%Pb-60%Sn)
(20%Pb-80%Sn)
(60%Pb-40%Sn)
