Calculate the number of vacancies per cubic meter in some metal at 631°C. The energy for vacancy formation is 0.89 eV/atom, while the density and atomic weight for this metal are 4.89 g/cm3 (at 631°C) and 63.52 g/mol, respectively.
Calculate the energy (in eV/atom) for vacancy formation in some metal, M, given that the equilibrium number of vacancies at 327oC is 4.49 × 1023 m-3. The density and atomic weight (at 327°C) for this metal are 19.3 g/cm3 and 40.50 g/mol, respectively.
Calculate the number of atoms per cubic meter in aluminum. The density and atomic weight of aluminum are 2.70 g/cm3 and 26.98 g/mol respectively. The value of Avogadro’s number is 6.02 x 1023 atoms/mol.
Extra credit assignment (Purely voluntary)
You are working as a Mechanical Engineer at United Technologies Research Center in Hartford, Connecticut. Your company is developing next generation of jet engines, which are light-weight and yet are more powerful than the currently used ones. This will cost a significant amount of fuel savings. At the core of the design are the blades that rotate at high speeds and deliver the required thrust for the aircraft. You are supposed to select materials for the construction of such blades. The possible strategies for such a job are:
1. Read up on jet engines with special emphasis on engine blades. How they work and what are the service conditions.
2. Identify these conditions and the relevant mechanical properties associated with those.
3. Determine which property is the most important, and the next most important etc… accordingly plan your strategy.
4. Read up on what are the materials currently being used and why?
5. Either do a little bit of research on why they are being used or suggest something that might perform even better.
Write 2-3 page report on your findings. One or two drawings/schematics would be nice. There is no hard and fast format as a long as the matter is logically presented. Discussions/collaborations with one another are permitted, but must submit individual report. However, this boss will not act as a consultant and there will be no responses to e-mails regarding this matter. If the boss likes the report, there will be nice semester-end bonus added to the grade. The report is due at the time of the final exam.