Microstructural Characterization and Thermal Properties of Aluminium Titanate/Porcelain Ceramic Matrix Composites

Abstract

Porcelain represents one of the most complex ceramics, formulated from a mix of clay, feldspar and quartz, sintered at temperatures between 1200• C and 1400• C, to form a glass-ceramic composite. Aluminium titanate (Al2TiO5) exhibits extremely good thermal shock resistance and low thermal conductivity, coupled with good chemical resistance in molten metals. In the present work, aluminium titanate/porcelain ceramics composites with dierent percentages of Al2TiO5 was prepared using powder metallurgy techniques. The microstructural, mechanical and thermal properties were characterized using XRD, SEM, dilatometer and a hardness meter. Thermal shock resistance behaviour under water quenching of the as-prepared ceramics was also evaluated. The results have revealed that the addition of aluminium titanate to porcelain matrix improves the properties of the aluminium titanate/porcelain ceramics.

Fine Ti‐dispersed Al2O3 composites and their mechanical and electrical properties

“…However, the measured Young's modulus and Vickers hardness values were higher than the theoretical values predicted for mixtures of Al 2 O 3 and Ti. This is attributed to the presence of TiAl 2 O 5 , which has been shown to be beneficial for improving hardness . The impurity effect of TiAl 2 O 5 on Ti particles such as dissolving small amount of Al and/or oxygen elements was also considered to contribute to the increased Young's modulus and Vickers hardness.…”

“…This is attributed to the presence of TiAl 2 O 5 , which has been shown to be beneficial for improving hardness. 28 The impurity effect of TiAl 2 O 5 on Ti particles such as dissolving small amount of Al and/or oxygen elements was also considered to contribute to the increased Young's modulus and Vickers hardness. 29 The decreased flexural strength of Al 2 O 3 /Ti composites was ascribed to lower flexural strength of Ti than that of Al 2 O 3 .…”

“…As motioned above, the small amount of TiAl 2 O 5 can contribute to crack deflection and hence adsorbs crack propagation energy to increase fracture toughness owning to the "pinning effect" in spite that the intergranular microcracking in TiAl 2 O 5 greatly limits its fracture toughness. 28 When Ti content is below 20%, pinning effect of small amount of TiAl 2 O 5 is predominant, leading to increased fracture toughness than that of monolithic Al 2 O 3 . On the other hand, with the increase in the amount of TiAl 2 O 5 , the effect of intergranular microcracking in TiAl 2 O 5 cannot be ignored and becomes the leading factor.…”

Role of CeAl11O18 in reinforcing Al2O3/Ti composites by adding CeO2

“…Due to the weakened interfacial reaction between Al 2 O 3 and Ti after CeO 2 addition, the increased amount of metallic Ti particles, which could contribute to toughening from ductile fracture, resulted in the higher fracture toughness. In Al 2 O 3 /Ti composite without CeO 2 , interfacial reaction product of TiAl 2 O 5 was generated and these particles fill up grain boundaries and weaken the bonding force, 20,21 which limits the increase in fracture toughness 39 …”

“…In Al 2 O 3 /Ti composite without CeO 2 , interfacial reaction product of TiAl 2 O 5 was generated and these particles fill up grain boundaries and weaken the bonding force, 20,21 which limits the increase in fracture toughness. 39 For further investigation, crack propagation behavior is shown in Figure 9. It is found that the toughening mechanisms are mainly ascribed to transgranular fracture and crack deflection [ Figure 9A]) and crack bridging by Ti [ Figure 9B] and elongated CeAl 11 O 18 particles [ Figure 9C].…”