Question

Rapid cooling (thermal shock) of a thin layer of material causes a thermal shock stress. the thermal shock stress can be estimated by Εα(ΔT) σ, - σ 1-v Assume that a piece of materials in the table below contains a crack of a depth a 0.5 mm, calculate the surface temperature change necessary to cause brittle fracture for each material [6 marks]. Rank the materials in thermal shock resistance from the largest to the least [2 marks] hint: Y-0.72 small half-circular surface Materials KC (MPa m12 Coefficient of Modulus of Poisson's Ratio Thermal Expansion [10°C] Elasticity [GPa] 69 Soda-lime glass 0.76 9.1 0.20 SiC 3.7 4.5 390 0.22 Titanium 43 8.9 110 0.35

Answer 1

bailura &rk -Sada lime lod 0001 7 0.t6 0 P(0.12) Jeu. Ski) s - 20.64Mpa. Ob Pil Ed (AT 1-19 AT 34C CroS (26.6= 1- 0.2 Sic 3.4 129.69 M Pa 072 0.5x103 ~ヒdA介 Baox10) (4SK)(T (199.61x109) 1-0.29 t aiuん 1507.2529 Mpa 0.t2

AT 1-d 1507.9824K106)10x101) (8.K09 (41) | -0.35 AT H000.73° Hen moko tomperatuo dibdb. &hock resistanco. TIHaNum sfcS0da.line ylors H ATA2w PxPar