Tensile behavior of AZ91 alloy containing silver and under different casting conditions

Subject Areas : journal of New Materials

Pouria Kamaei ¹ (MSc graduated of Materials Science and Engineering, Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran)
Mehdi Khorasanian ² (Assistant prof. of Materials Science and Engineering, Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran)
Seyed Reza Alavi Zaree ³ (Associate prof. of Materials Science and Engineering, Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran)
Mostafa Eskandari ⁴ (Assistant prof. of Materials Science and Engineering, Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran)

Received: 2023-08-22 Accepted : 2023-11-05 Published : 2023-01-21

Keywords: Microstructure, casting, AZ91 magnesium alloy, chilled solidification, Tension test,

Abstract :

Abstract
The aim of the present research was to study the behavior of AZ91 magnesium alloy under cold and hot tension tests. The alloy was cast under solidification conditions with and without a chill. During the preparation of the melt, silver was added in different amounts to the melt. The uniaxial tensile test was performed at room temperature and at 120 °C on the samples with different percentages of silver and with different solidification conditions. The results showed that the presence of silver in the alloy caused a change in the morphology of the Mg17Al12 phase and a change in the microstructure and tensile properties of the alloy. The change in the morphology of this phase has a significant effect on the mechanical properties of the alloy. This phase is a brittle phase, and along with the hexagonal crystal structure of magnesium, can deteriorate the tensile behavior of the alloy. The best tensile behavior was obtained for the sample with 0.1 wt% silver without a chill. In this sample, the Mg₁₇Al₁₂ phase appeared as a dispersed phase with less continuity at the grain boundaries. When the amount of silver increased to 0.4 wt%, the tensile properties decreased significantly due to the increase of the size of this phase in the microstructure. solidification with a chill had no positive effect on the tensile properties of the alloy at high and low temperatures.
Introduction:The aim of the present research was to study the behavior of AZ91 magnesium alloy under cold and hot tension tests. The alloy was cast under solidification conditions with and without a chill. During the preparation of the melt, silver was added in different amounts to the melt.  Methods: AZ91 specimens were produced using permanent mold casting. The raw materials were heated in the form of commercial ingots in an electric furnace, and after melting, silver was introduced into the melt in the form of commercial pure granules.
Findings:
In Figure 3, the results of room temperature tensile tests on samples containing 0.1 wt% of silver and with different solidification conditions namely sample 1 (casting without chill at 650 ˚C), sample 2 (casting with chill at 750 ˚C) and Sample 3 (casting with chill at 850 ˚C) is shown.

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