Influence of graphite and solidification under vibration on mechanical and machining properties of hypereutectic (Al-Si)‎ alloy

Abstract EN

Hypereutectic aluminum–silicon (>13 %Si) alloys have been used for many engineering applications due to their properties.

A continuing problem with these alloys is that they are difficult to machine, tool wears rapidly due to the hardness and abrasive nature of the Si particles, so repairing this problem is very important.

In this work, the hypereutectic Al-Si alloy samples were prepared by stir casting.

Effect of solidification under mechanical vibration with three frequencies (32.5, 100, 124.5Hz) and constant amplitude (0.5 mm) as well as an addition of 0.3 % graphite was studied.

Several mechanical, physical, and machineability tests were carried out.

Machineability tests were related to the surface roughness and tool life.0T a maximum width of flank wear of 300μm was considered0T as a criterion of tool life.

Carbide tips type P10 with dry turning operations were used at a constant depth of cut of 0.5 mm.

Four cutting speeds (15, 21, 31, 45m / min) for each of which four feed rates (0.005, 0.008, 0.01, 0.016 mm / rev) were used as the machining conditions.

Results showed that adding (0.3 % Graphite) to hypereutectic (Al–Si ) alloy accompanied with solidification under vibration improves its microhardness by (26 %) and tensile strength by (102 %) and modulus of elasticity by (20 %).

The results of machining experiments showed depressing in tool flank wear and improving surface finish.

This was true for all regarded machining conditions.

The surface roughness was reduced by (20-38 %) with the used machining conditions, while an increase of (76 -94 %) in tool life was achieved.