Materials Science I, 95/96: Test #1

1. A process is known to follow the Arrhenius relationship, and a rough test shows that, at temperatures near the room temperature, its rate is roughly doubled for every 10 ? rise. What is its approximate activation energy?
 
2. Write down the equation and appropriate boundary conditions that describe the diffusion of hydrogen inside a container at high temperature, into the "thick" steel wall of the container.
3. Copper has a cubic crystal structure and the slip systems {111} <110>. Draw the unit cell, a slip plane and its associated slip directions. How many independent slip systems are there in total?
 
4. Two fairly common types of 2-dimension crystallographical defects are the twin boundary. Using square grids to represent the crystal lattice, sketch an example of each. 
 
5. Use the Griffith crack model to explain why a glass plate can support a heavy load, when the glass sits on top of a flat surface, but breaks if it is placed on an uneven surface.
 
   

END


<  Back >