21-Mat-A4 Deformation Behaviour and Properties of Materials, December 2019: worked solutions

Paper format. National Exams, December 2019 — 10-Met-A4, Structure of Materials. Three hours, closed book, one approved calculator (Casio or Sharp). Seven questions of 20 marks each; the rubric asks for any five, with only the first five in the answer book marked. All seven are solved here, because this set is a study resource rather than an exam script. All necessary equations, constants and an error-function table are provided in the exam's own appendix (reproduced where used below).

Note on the exam title. The printed exam header reads 10-Met-A4, Structure of Materials. Only Question 6 (dislocations, slip, resolved shear stress) touches mechanical/deformation properties directly; the paper as a whole is a broad introductory materials-science survey — atomic structure, bonding, crystal structure/directions/planes, point defects, XRD, dislocations and phase diagrams — and is answered as such below.

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

W. D. Callister and D. G. Rethwisch, Materials Science and Engineering: An Introduction, 10th ed. — atomic structure and bonding (Ch. 2), crystal structure and Miller/Miller–Bravais indices (Ch. 3), imperfections/point defects (Ch. 4), XRD (Ch. 3), dislocations/slip (Ch. 4, 7), phase diagrams (Ch. 9).
G. E. Dieter, Mechanical Metallurgy, 3rd ed. — resolved shear stress, slip systems, cross slip.

21-Mat-A4 Deformation Behaviour and Properties of Materials: December 2019