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22-Mec-B8 Engineering Materials: Undated paper

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Corrosion rate of iron from its corrosion current density
  2. Question 2 Inward flux of carbon during carburizing, from Fick's first law
  3. Question 3 Atom count and dopant fraction in a silicon wafer
  4. Question 4 Magnesium sacrificial anode in a hot water heater
  5. Question 5 Three consolidation routes for aerospace FRP laminates, and where each may fly
  6. Question 6 ABS versus phenolic for an engine-mounted box
  7. Question 7 Three aluminium alloys for transport-aircraft floor beams
  8. Question 8 Necking of a ductile wire — Considère's criterion

Start with Question 1 →

Paper format. National Exams — 16-Mec-B8 Engineering Materials, undated sitting (the printed footer reads 16-Mec-B8/May 2019). Three hours; any non-communicating calculator permitted. Eight problems, all of equal value; any FIVE constitute a complete paper, so each problem is worth 20 marks. Candidates are urged to submit a clear statement of any assumptions made. All eight problems are solved below.

Reference texts (22-Mec-B8 Engineering Materials).

  • Askeland & Wright, The Science and Engineering of Materials, 7th ed. — the primary syllabus text.
  • Callister & Rethwisch, Materials Science and Engineering: An Introduction, 10th ed.
  • Dieter, Mechanical Metallurgy, 3rd ed. — Considère's construction and plastic instability.
  • Shackelford, Introduction to Materials Science for Engineers, 8th ed.
  • Fontana, Corrosion Engineering, 3rd ed. — Faraday's law, corrosion rates and cathodic protection.
  • Ashby, Materials Selection in Mechanical Design, 5th ed. — selection criteria and material indices.
  • Polmear, Light Alloys, 5th ed. — aluminium tempers and Al–Li alloys.

Note on this sitting. Five of the eight problems restate standing 22-Mec-B8 archetypes with fresh or unchanged data — the magnesium sacrificial anode, the FRP consolidation essay (problem 5, now asking for three routes and for their applicability to primary versus secondary structure rather than four routes and their trade-offs alone), the ABS-versus-phenolic selection (problem 6), the aluminium–lithium floor-beam substitution (problem 7, restated in kilograms rather than newtons) and Considère necking (problem 8). Problems 1, 2 and 3 are new to the subject: they are Faraday's-law corrosion rate, Fick's first law applied to carburizing, and an atom-counting exercise on a silicon wafer. Every calculation has been re-worked from this paper's own numbers.