Answer the following questions by referring to the Cu-Al phase diagram shown below.
(a) What is the lowest temperature at which a liquid can be found in a system of any composition of Cu-Al ?
(b) A common alloy composition used in airplanes is 4 at. % Cu - 96 at. % Al. For this overall system composition, identify what phases are present at 500 degrees C. Select all phases present:
Liquid
Vapor
Al
Cu
CuAl2
CuAl
Cu1.5Al
Cu9Al4
Cu4Al
Cu0.75Al0.25
(c) What phases are present at a 50/50 mixture of Al/Cu at 660 degrees C? Select all phases present:
Liquid
Vapor
Al
Cu
CuAl2
CuAl
Cu1.5Al
Cu9Al4
Cu4Al
Cu0.75Al0.25
(d) In the previous question, you should have identified two phases. What is the phase fraction of the first phase you identified?
(a) From 530 to 570.
(d) 0.41
any ideas for b)and c) ?
for (c) ans is liquid and Cu1.5Al
(B) Al & CuAl2
d = 0.41 how can i calculate that result?
The phase fraction is calculated using the 'Lever Rule'.
I can't figure out how to do it, but it involves using this formula-
X = (c-b)/(a-b)
Where a, b, and c are distances between x-coordinates at various phase boundaries.
But the phase diagram in this question is weird and I can't figure out where the points are so I don't know the distances required for the formula.
To answer these questions, we need to refer to the Cu-Al phase diagram provided. Let's go through each question step by step:
(a) To find the lowest temperature at which a liquid can be found in a system of any composition of Cu-Al, we need to identify the liquidus temperature. The liquidus temperature is the temperature boundary that separates the liquid phase from the solid phases. It represents the lowest temperature at which a liquid can exist.
To determine this temperature, locate the liquidus line on the phase diagram and read the corresponding temperature value. This value represents the lowest temperature at which a liquid can be found in the Cu-Al system, regardless of the composition.
(b) The given composition is 4 at. % Cu - 96 at. % Al. To identify the phases present at 500 degrees C for this composition, we need to locate the temperature of 500 degrees C on the phase diagram and then examine the corresponding phase regions.
Find the temperature of 500 degrees C on the temperature axis of the phase diagram. Then, determine which phase regions intersect this temperature line. The phases that intersect the 500 degrees C temperature line are the ones present for the given composition.
Select the phases from the list provided, which correspond to the phase regions intersecting the 500 degrees C temperature line.
(c) For a 50/50 mixture of Al/Cu, we want to determine the phases present at 660 degrees C. Locate the temperature of 660 degrees C on the phase diagram and identify the phase regions intersecting this temperature line.
Select the phases from the list provided, which correspond to the phase regions intersecting the 660 degrees C temperature line.
(d) In the previous question, you should have identified two phases at the 50/50 mixture of Al/Cu at 660 degrees C. To find the phase fraction of the first identified phase, we need to refer to lever rule.
The lever rule is used to determine the phase fraction of each phase present in a two-phase region. It is a ratio of the distance between the composition of interest and the phase boundary, divided by the distance between the two phase boundaries.
Measure the distance between the composition 50/50 Al/Cu and the phase boundary of the first phase identified. Then, measure the distance between the two phase boundaries.
To calculate the phase fraction of the first phase, divide the distance between the composition of interest and the phase boundary of the first phase by the distance between the two phase boundaries. This will give you the phase fraction of the first phase.