The evaluation of microstructure, grain boundary character and micro texture of [Al/Si3N4/Al2O3] P nanocomposites fabricated through PM route and its influence on compressive and three-body wear properties

Abstract

The compressive properties and 3 body wear characteristics of powder metallurgical (PM) processed [Al/Si _3 N _4 /Al _2 O _3 ] _P Nanocomposites with single and combined reinforcement of Al _2 O _3 and Si _3 N _4 reinforcing particles having different compositions (1%, 2% and 3%) were studied and evolution of microstructure, grain boundary character and micro texture of fabricated [Al/Si _3 N _4 /Al _2 O _3 ] _P Nanocomposites was investigated through EBSD in the present research work. The fraction of high angle boundaries (HAGBs) were observed more in combined reinforcing samples of Al _2 O _3 and Si _3 N _4 whereas a single reinforcing sample of Al _2 O _3 and Si _3 N _4 showed fewer HAGBs. Micro texture results showed the strong textures components near to {112}〈111 〉 Cu and {110}〈111 for pure sintered Al sample P and mixed reinforcement composites (M _1 , M _2 and M _3 ) > P whereas for single reinforcing sample showed weak textures near to transverse direction. Out of all fabricated composites, 2% mixed Al _2 O _3 and Si _3 N _4 reinforced composite revealed the maximum ultimate compressive strength (209.98 MPa) and least wear rate (0.1 mm ^3 /min mm ^3 /N-cm for 1 kg load and 3.5 mm ^3 /N-cm for 2 kg load) attributing formation of nanocluster causing grain boundary pinning effect. The dominant failure mechanism for all samples was also detected and found to be a mixed-mode ductile failure mechanism for 2% mixed Al _2 O _3 and Si _3 N _4 reinforcement composite while other sample failed through ductile as well as mixed-mode mechanisms.

Keywords

• nanocomposites
• powder metallurgy
• EBSD
• micro texture
• TEM