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Materials Science Flashcards

7 cards from real EIT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. What is the coordination number for an atom in a face-centered cubic (FCC) crystal structure?

    Answer: 12

    In an FCC structure, each atom is surrounded by 12 nearest neighbors, giving a coordination number of 12.

  2. Which of the following crystal structures has the highest atomic packing factor (APF)?

    Answer: Face-centered cubic (FCC)

    FCC has an APF of 0.74, which is the highest among the listed structures (BCC = 0.68, SC = 0.52, diamond = 0.34).

  3. At what temperature does the eutectoid reaction occur in the iron-carbon phase diagram?

    Answer: 727°C

    The eutectoid reaction (austenite → ferrite + cementite) occurs at 727°C and 0.76 wt% C, producing pearlite.

  4. What is the eutectoid composition in the iron-carbon phase diagram?

    Answer: 0.76 wt% C

    The eutectoid point occurs at 0.76 wt% C, where austenite transforms directly to pearlite (ferrite + cementite) at 727°C.

  5. What type of point defect involves a missing atom at a lattice site?

    Answer: Vacancy

    A vacancy is a point defect where an atom is absent from its regular lattice position.

  6. Fick's First Law of diffusion states that flux J equals:

    Answer: -D(dC/dx)

    Fick's First Law is J = -D(dC/dx), where flux is proportional to the negative concentration gradient and the diffusion coefficient D.

  7. The primary distinction between steel and cast iron in the Fe-C phase diagram is:

    Answer: Steel contains less than 2.14 wt% C; cast iron contains 2.14–6.70 wt% C

    The eutectic point at 2.14 wt% C divides the Fe-C system: alloys below 2.14 wt% C are steels, and those above are cast irons.