Effect of Silicon Addition on Friction and Wear Behaviour of High Tensile Brasses

Copper alloys with the main alloying elements Zn, Al, and Ni are well known for their impact, wear, and corrosion resistance. Different fabrication techniques and alloying elements can be used to modify the microstructure and properties. The effect of shell mould and permanent mould techniques on the microstructure, microhardness, and wear behaviour of high tensile brass and nickel aluminium bronze (RB031, RB032, and NAB) was investigated in this work. For permanent mould fabricated alloys, optical microscopic analysis revealed a homogeneous microstructure with fine grains. The RB032 alloy had a higher proportion of Mn 5 Si 3 particles than the other two high tensile brasses (RB031 and RB032). In the case of NAB alloy, both fabrication techniques revealed similar phases composed of - phase,'phase, and intermetallic phases (I, II, III, and IV). Higher cooling rates in Permanent Moulded Cast alloys resulted in equiaxed structures, which were especially noticeable in RB032, which had 31% smaller grain size than Shell Moulded Cast alloy. RB032 (PM) microhardness values were 2.3% higher than Shell Moulded (SM), with RB032 exhibiting the highest increment. Permanent Moulded alloys outperformed Shell Moulded alloys in terms of friction and wear rate, with RB032 (PM) having 44% lower friction and 5.8% lower wear rate. The wear mechanisms differed, with RB031 exhibiting abrasive wear and RB032 and NAB(AB2) exhibiting adhesive wear.