Effect of Mg Content and Heat Treatment on the Mechanical Properties of Low Pressure Die-Cast 380 Alloy

Abstract

The present study was carried out on a 380 alloy containing 9.13% Si, 3.22% Cu, 1.01% Fe, 0.06% Mg, 0.16% Mn, and 2.28% Zn. The magnesium level was increased to 0.3 and 0.55%, by adding pure Mg to the melt. Tensile and fatigue samples were produced using low pressure die casting. The results show that the average dendrite arm spacing was about 6 μm. Increasing the amount of Mg from 0.06% to 0.55% increased the volume fraction ofπ-Al8Mg3FeSi6and Q-Al5Cu2Mg8Si6phases from 0.8% to 1.7%. Following solutionizing at 490°C for 8 h, the maximum ultimate tensile strength was obtained from alloys containing 0.3% Mg. Further increases in Mg content resulted in an increase in the amount of insoluble intermetallics and, hence, low tensile strength. Aging at 155°C for times up to 25 h resulted in a linear increase in the alloy strength regardless of the amount of added Mg. Aging at 220°C, however, revealed multiple peaks corresponding to the precipitation of various phases. A good relation between the applied force and the number of cycles prior to failure was established. The alloy containing 0.3% Mg produced the best fatigue resistance. The effect of porosity was more pronounced on the fatigue samples than on the tensile bars.

Effect of Mg addition on microstructure and mechanical properties of AlSi12 alloy produced by high-pressure casting method

“…However, the addition of magnesium caused the AlSi12 alloy to absorb much lower energy. These results are similar to the different studies reported in the previous literature (Hurtalová et al , 2013; Morin et al , 2016). It is believed that the magnesium-containing alloys absorb less energy in the tensile test and less energy in the impact test because of the brittle Mg 2 Si in their structure compared to the AlSi12 alloy.…”

“…With the increase of the Mg ratio, the intensity of intermetallics formed in the structure increased and China scripts were formed. Morin et al (2016) found similar secondary phases in AlSi 9 Cu 3 Fe alloy. In the literature, there are studies in which similar microstructures and components are observed on 6082 aluminum alloy (Mrówka-Nowotnik et al , 2007) and AlSi 9 Cu 3 alloy (Tillová et al , 2012).…”

“…With the increase of the Mg ratio, the intensity of intermetallics formed in the structure increased and China scripts were formed. Morin et al (2016) found similar secondary phases in AlSi 9 Cu 3 Fe alloy. In the literature, there are studies in which similar microstructures and The images obtained as a result of mapping analysis made with SEM-EDS on microstructure samples are shown in Figure 4(a)-(d).…”