Volume 39, Issue 2 (March 2011)
Pore Independent Crack Propagation of Glass-Alumina Functionally Graded Materials
Crack propagation of glass-alumina functionally graded materials prepared by a novel freeform fabrication method was investigated. Pores were intentionally introduced by partial decomposition of poly vinyl alcohol gel. Preferential distribution of pores adjacent the alumina particles is confirmed due to the integrated liquid-phase sintering process, especially the migration of the activated alumina interfaces towards the equilibrium state. Crack propagation and distribution were directly observed by scanning electron microscopy. Cracks propagate through the weakly bonded interfaces which finally cause the glass matrix to fracture. However, pores have little effect on the crack propagation.