Effect of the cooling process on the mechanical properties and microstructural behavior of extruded AZ31 and AM50 Mg alloys

During the extrusion of magnesium alloys, temperature change could have a significant effect on the outcome. When this effect is not considered, some commonly known defects might be observed, such as hot cracking. In this study, all samples consist of extruded AZ31 and AM50 magnesium alloys as a solid profile, but the methods by which they are cooled, such as air cooling and water quenching, vary. The effects of cooling methods on tensile-compression behavior and the microstructural properties of the samples were investigated. Test samples were obtained in extrusion direction and perpendicular to the extrusion direction separately for mechanical tests. The main purpose of this study was to investigate the effect of different cooling methods on the mechanical properties and microstructural behavior of AZ31 and AM50 magnesium alloys after extrusion, once different cooling methods were applied. According to the microstructural investigation results, an AM50 magnesium alloy has a finer grain structure as compared with an AZ31 alloy according to both cooling methods in the extrusion process. The average grain size values of both alloys were found to be higher for water cooling. Cooling methods have significant effects on the tensile properties of both alloys, depending on their extrusion directions.