Using Knovel to Complete Chapter Exercises <ul><ul><li>4/09 </li></ul></ul>
The basic search is the primary tool used in completing the exercises. To access the basic search, click on the ‘ Search Knovel ’ tab on the left of Knovel’s homepage.
To learn what various Boolean operators do and to learn some general search tips click on the ‘ search tips ’ tab.
If the icon appears next to a title in the basic search then it contains an interactive table.
Shown below is an interactive table. You can filter data, convert units or even export the table in a variety of formats including to an excel sheet.
Shown below is an equation plotter. The equation plotter is represented by the symbol and is a special interactive graphing applet.
The icon indicates graph digitizer interactivity. Shown below is a phase diagram being utilized by the graph digitizer function.
Let’s take a look at the chapter 10 exercise. <ul><li>We would like to produce a Sn-Pb composite (commonly known as solder) that has just reached 98 wt% Sn at 423 K (105˚C). Determine the phase type of tin that has just formed at this temperature. </li></ul><ul><li>Suppose a 1000-kg mixture of iron carbide with 0.1 wt% C is held at 1073 K (800˚C). How many kg of carbon can be added to the mixture before any γ forms? How many pounds of carbon must be added to the original mixture to begin forming a γ + Cementite alloy? </li></ul><ul><li>3)What is the composition of liquid Ag found in a 50 wt% mixture of Ni and Ag at 1273 K (1000˚C)? </li></ul>
Here we see a graph digitizer for the binary phase diagram of tin and lead. Using it we find that the phase that is formed is βSn.
We can see on this phase diagram that at 0.1 wt% C in the phase diagram @ 800˚C the phase is α + γ. The maximum allowed carbon content (before reaching a state of only γ phase) is approximately 0.3 wt% C.
Now we solve for the amount of carbon that can be added before forming the γ phase. Since the original composition is 0.1 wt% C the initial mass of C is: Therefore we can write down the following expression where x is the mass of Carbon that must be added to the mixture to create a 0.3 wt% Iron carbide mixture:
Solving for the amount of carbon that must be added to the original mixture to get the γ + cementite phase. Now we wish to find the composition of C needed to make the solution completely γ + Cementite. Carefully examining the phase diagram we see that at a temperature of 800˚C a composition of about 0.95 wt% of C would be the threshold of creating a phase of γ + Cementite. Now the question is how much C must be added to the original mixture to obtain this wt %. To do this we solve for x in the following equation (just as in the first section of the question):
In order to find the liquid Ag composition of such a mixture at the given temperature we must use the lever rule function on the graph digitizer.
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