Microstructure and wear behaviour of ceramic particles strengthening NiAl based composite

Abstract

In the present paper, the NiAl based composite strengthened by TiC and ZrO2 ceramic particles (NiAl–TiC–ZrO2 for short) was prepared by the hot press aiding exothermic synthesis (HPES) technique to get a material with good wear properties. OM, SEM and TEM were employed to investigate the microstructure of the NiAl–TiC–ZrO2 composite. The mechanical properties and wear behaviour were studied by compression and dry sliding wear tests. The results showed that the NiAl–TiC–ZrO2 composite possesses fine microstructure, but the TiC and ZrO2 particles tended to agglomerate along NiAl phase boundary. Further observations revealed that the ultrafine ZrO2 particles contained stacking faults and microtwins inside and thin amorphous layer was generated along some interfaces of NiAl and TiC phases. Compression tests exhibited that the addition of TiC and ZrO2 particles could increase the strength of the NiAl–TiC–ZrO2 composite significantly. Wear tests results demonstrated that the NiAl–TiC–ZrO2 composite had relative good wear resistance at high temperature. Especially at 973 and 1073 K, the composite exhibited self-lubrication behaviour, which might be attributed to the lubricant film formed on the worn surface. TEM observation on the lubricant film revealed that it was composed of amorphous matrix and nanoparticles. Moreover, TEM observation found the composite near the worn surface contained ultrafine microstructure. When the temperature increased or decreased, the lubricant film would be spalled partly, which led to the increasing of the friction coefficient and wear rate.