Effects of Trace Elements on Thermal and Mechanical Properties of Al-Zn-Cu Based Alloys Using Extrusion

Thermal properties and microstructure of Al-4 wt.% Zn-2 wt.% Cu x (x = 2 wt%. Mg, 2 wt%. Sn, 0.7 wt.% Mg-0.7 wt.% Sn-0.7 wt.% Ca) alloys on cast and extrusion have been investigated with extrusion temperature of 400 degrees C. Al-4 wt.% Zn-2 wt.% Cu alloy was composed of Al and Al2Cu phases. By adding Mg contents, Al2Mg3Zn3 phase was increased and Al2Cu phase was decreased respectively. During hot extrusion, elongated in the extrusion direction because of severe deformation. The thermal conductivity with temperature and composition of as-extruded Al-4 wt.% Zn-2 wt.% Cu x alloys decreases with adding 2 wt.% Mg, 2 wt. % Sn contents from 190.925 and 196.451 W/mK but thermal properties of addition of 0.7 wt.% Mg-0.7 wt.% Sn-0.7 wt.% Ca element slightly reduced from 222.32 to 180.775 W/mK. The ultimate tensile strength (UTS) for Al-4 wt.% Zn-2 wt.% Cu alloy was 121.67 MPa. By adding 2 wt.% Mg contents, tensile strength was dramatically increased with 350.5 MPa.