The Role of Nano Particles Additives on The Wear Properties of Al-Pb alloy

Abstract

The Al-Pb alloy is one of the important alloys, especially for bearings materials. The main problem of Al-Pb alloy is the difference in melting point and immiscibility between aluminum and lead. In this research mechanical alloying method was used to produce Al- 10%Pb- 4.5%Cu by mixing the constituent in a ball mill under argon atmosphere for two hours at 150 rpm , then it was pressed with different applied loads (44100, 49000, 53900, 58800 and 63700N) and at three sintering temperatures (350, 450 and 550℃). The results show that sintering temperature was  the main factor affecting on the microstructure of alloy. The grain size was reduced with increasing sintering temperature and applied load. The results revealed that the best hardness and compressive strength was obtained with 58800N applied load and 450℃ sintering temperature due to the formation of CuAl₂ as well as good distribution of Pb.

Alumina in a form of micro and nano particles size resulted in a decline in hardness and wear resistance, while micro Al₂O₃ improved compressive strength and then decreased at high concentration (2wt. %). The addition of micro and nano SiC resulted in  reduced hardness. Micro SiC improves wear resistance and slightly improved the compressive strength while nano SiC increased to some extent the compression strength and reduced wear resistance. The grains size decreased with the increase of the percentage of Al₂O₃ and SiC (micro and nano) until 1.5% Al₂O₃ and 1%SiC addition. X-ray diffraction indicated the formation of new Al-Cu intermetallic compound (Cu₉Al₄) in the alloy containing Al₂O₃ or SiC associated with disappears of CuAl₂.

Keywords: Mechanical alloying, Sintering, SEM, EDS, hardness, compressive strength, Wear.