Effect of Rapid Solidification and Addition of Cu3P on the Mechanical Properties of Hypereutectic Al-Si Alloys

Abstract

The combined processes; rapid solidification, addition of Cu 3 P compound and heat treatments to improve the mechanical properties of the hypereutectic Al-13Si, Al-20Si and Al-20Si-1.5Fe-0.7Mn alloys (in wt. %) was studied. Optical microscopy and scanning electron microscopy were used to characterize the microstructures. The mechanical properties were evaluated by tensile tests. It was found that the cooling rate (20-50°C/s) used to solidify the alloys plus the addition of Cu3P compound favored the formation of fine primary Si and the transformation of the Al/Si eutectic from acicular to semi-transformed morphology. The spheroidization of the Al/Si eutectic after heat treatment caused an increase in the elongation (%) compared with the as-cast alloys. Al-13Si alloy showed the highest UTS and elongation (%) values, reaching values up to 215 MPa and 9.6%, respectively. On the other hand, the Al-20Si-1.5Fe-0.7Mn alloy showed the lowest UTS (180MPa) and elongation (3.4%) values. The formation of the Fe-intermetallic compounds caused a negative effect on the mechanical properties of the Al-20Si-1.5Fe-0.7Mn alloy.

Tribology of Si-rich TIG-deposited coatings on Zn–40Al–2Cu alloy

“…Regarding the general similarity between the size and morphology of Si P particles in Zn-40Al-2Cu and hypereutectic Al-Si alloys, different techniques can be used to modify the shape and distribution of Si P particles in the microstructure of Zn-40Al-2Cu alloy, the most important of which are heat treatment [4], rapid solidification [5,6], mechanical/thermo-mechanical processing [7][8][9], chemical modification [4,[10][11][12], and molten metal processing [13][14][15]. Some techniques are cost-intensive and need special equipment.…”