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The given table shows the solidification temperatures for various alloys of metal A and metal B - Leaving Cert Engineering - Question b - 2015
Question b
The given table shows the solidification temperatures for various alloys of metal A and metal B. % of metal B in alloy 0 10 20 30 40 50 60 70 80 90 100 Start of sol... show full transcript
Worked Solution & Example Answer:The given table shows the solidification temperatures for various alloys of metal A and metal B - Leaving Cert Engineering - Question b - 2015
Step 1
Draw the equilibrium diagram according to the given data;
Answer
To draw the equilibrium diagram, plot the solidification temperature data from the given table.
- Create a graph with the x-axis representing the percentage of metal B (0% to 100%) and the y-axis representing the temperature (in °C).
- Plot the start and end of solidification using the points from the table:
- Start of solidification for 50% B is 1380 °C.
- End of solidification for 50% B is 1220 °C.
- Connect these points to outline the liquid and solid phases, marking the liquidus line, solidus line, and pasty region.
- Specifically, label the 1250 °C line to visualize where 50% B falls on the diagram, which indicates the phase states.
Step 2
Label the diagram and describe the main features;
Answer
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Labels for Graph:
- Label the axes as ‘% of metal B’ and ‘Temperature (°C)’.
- Identify and label the Liquidus line (above which the alloy is fully liquid), the Solidus line (below which the alloy is completely solid), and the Past region (where both solid and liquid phases coexist).
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Main Features:
- Liquid Phase: From the Liquidus line upwards, the alloy is in a liquid state.
- Pasty Phase: Between the Liquidus and Solidus lines, some solid exists, indicating the beginning of solidification.
- Solid Phase: Below the Solidus line, the alloy is fully solid.
Step 3
Determine from the diagram, the ratio of the phases at 1250 °C for the alloy with 50% B;
Answer
To determine the ratio of phases at 1250 °C:
- Locate 1250 °C on the y-axis and draw a horizontal line to intersect with the Liquidus and Solidus lines.
- Measure the corresponding amounts of solid and liquid.
- Mass of solid: Based on the diagram, the mass of solid is determined to be 24 (calculated as per given values).
- Mass of liquid: The mass of liquid is determined to be 16 (calculated as per given values).
- The ratio can be expressed as follows:
- Ratio of phases = Mass of solid : Mass of liquid = 24 : 16 = 3 : 2.