21-Mat-A5 Phase Transformations and Thermal Treatment: December 2017

Paper format. National Exams, December 2017 — 10-Met-A5, Mechanical Behaviour and Fracture of Materials. Three hours, closed book, any Casio- or Sharp-approved calculator permitted. Eight questions of 20 marks each; the rubric states that five questions constitute a complete paper and that only the first five appearing in the answer book are marked. All eight are answered here, because this set is a study resource rather than an exam script. Several sub-parts explicitly call for an essay-format answer, and the rubric rewards clarity and organisation, so those answers are written as structured prose rather than as note form.

Reference texts. The answers below are keyed to the works normally recommended for this syllabus code:

• G. E. Dieter, Mechanical Metallurgy, 3rd ed. — dislocation theory and slip (Ch. 4–5), strengthening mechanisms (Ch. 6), fracture (Ch. 7), fatigue (Ch. 12), creep and stress rupture (Ch. 13).
• W. D. Callister and D. G. Rethwisch, Materials Science and Engineering: An Introduction, 10th ed. — dislocations and slip systems (Ch. 7), failure: fracture, fatigue and creep (Ch. 8).
• M. F. Ashby and D. R. H. Jones, Engineering Materials 1 & 2 — fast fracture and toughness, fatigue crack growth, creep mechanisms and deformation-mechanism maps.
• R. E. Reed-Hill and R. Abbaschian, Physical Metallurgy Principles — crystallography of slip and twinning, stereographic projections, Schmid's law.
• ASM Handbook, Vol. 11 (Failure Analysis and Prevention) and Vol. 19 (Fatigue and Fracture) — fractography and environmental cracking.
• Test standards cited where relevant: ASTM E8/E8M (tension), E139 (creep and stress rupture), E466/E647 (fatigue and fatigue crack growth rate), E399/E1820 (fracture toughness).