2. Introduction to solidification of casting alloys. Phase diagram for Al-Si. Phases during cooling. Different cooling rates throughout cast engine head.

5.  Simple systems have a melting temperature and a boiling temperature  Engines made from alloy of aluminum and silicon  More complicated in alloys

6.  What is an alloy  Not a compound ◦ H 2 O ◦ CH 4  Mixture of two or more metals in any proportion  Aluminum too soft, weak  Add silicon to harden and strengthen

7.  Aluminum and silicon come out of the melt and form separate components at the microscopic level  Rather than melting and boiling temperatures, look at Phase Diagrams

9. Solidus Liquidus Eutectic

12. ◦ Outside cools first  Solid outer shell  Molten inner core, cools later, puts outer shell in tension ◦ Different cooling rates lead to different microscopic structures ◦ Mismatch in microscopic structures create internal stresses

13.  …Stresses and Strains