"Numerical simulation of thermal shock of alumina disks with different surface finish"

A.G. TOMBA MARTINEZ; A.L. CAVALIERI

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY

ELSEVIER SCI LTD

Año: 2001 vol. 21 p. 1205 - 1212

0955-2219

Disks of commercial alumina were fabricated by slip casting and sintering. Two surface treatments were performed: a coarse machining, using a diamond wheel (70 grit) and a fine one with SiC papers (120/320 grit). Residual stresses were measured by X-ray diffraction and the fracture strength of the specimens were determined in biaxial flexion using a ball on discontinuous ring fixture.      The thermal shock resistance of the disks was evaluated by sudden cooling with a high-velocity air jet. The temperature differential between the disk and the air jet was incremented in 10°C until crack propagation was detected and the critical temperature differential (DTC) was determined.      Temperature and stress distributions during air impinging were calculated using a finite element analysis. Three models were proposed for the calculations and the results were analysed comparatively. Experimental data (DTC values and crack patterns) were explained on the basis of the calculated stresses.