Characterisation of in situ Al–TiB₂ nanocomposite powder synthesised by mechanical alloying

Abstract

Production of in situ Al–TiB₂ nanocomposite powder was studied using mechanical alloying (MA). Two approaches were used to obtain Al–20TiB₂ (wt-%) nanocomposite powder. In the first approach the synthesis of Al–20TiB₂ (wt-%) was investigated by ball milling an elemental Al–Ti–B powder mixture. The second approach involved a double step milling procedure to achieve an Al–20TiB₂ (wt-%) composite powder. The microstructure of as milled powder particles was investigated by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The thermal behaviour of MA powders was studied by differential scanning calorimetry (DSC). From these studies it was possible to conclude that TiB₂ can be formed in situ using the second approach without the production of undesirable phases; however, the first approach tends to form an undesirable Al₃Ti intermetallic phase in addition to the TiB₂ ceramic reinforcement.

Keywords:

• Nanocomposite powder
• Al–TiB₂
• Mechanical alloying
• Thermal stability

Acknowledgement

Sadeghian' sincere thanks go to the Deutscher Akademischer Austauschdienst (DAAD) for supporting the project.