Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format. National Exams, December 2019 — 10-Met-A5, Mechanical Behaviour and Fracture of Materials. Three hours, closed book, Casio/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.
Nothing on the paper is a phase-transformation or heat-treatment question in the TTT/CCT, hardenability or tempering sense; the syllabus actually examined is crystallography of slip and twinning, dislocation theory, creep, fatigue, toughness and fracture mechanics, and safe-life fatigue design.
Q4(a) states explicitly that the plate is semi-infinite and gives a service tensile stress (450 MPa), so it is solved using the free-surface geometry correction that detail calls for, alongside a cross-check against the simpler through-crack assumption.
Reference texts. The answers below are keyed to the works normally recommended for this syllabus code:
