Annealing Effects after Various Thermo-Mechanical Treatments on Microstructure and Mechanical Properties of Wrought Magnesium Alloy ZK60

Abstract

The magnesium alloy ZK60 received from Dead Sea Magnesium in direct-chill cast condition was extruded at T = 350• C using an extrusion ratio of ER = 12. The extruded bars were severely plastically deformed at 250• C by either equal channel angular pressing or swaging. While swaging led to similar grain renements as observed after equal channel angular pressing, yield stress and tensile strength values were by far superior in the swaged material. This result is explained by the unfavourable 45• texture component of the (0002) pole gure that develops during the massive shear deformation in equal channel angular pressing. Unlike equal channel angular pressing, the grain orientation after swaging is similar as in the as-extruded condition. Annealing at elevated temperatures indicates very low thermal stability of microstructure and mechanical properties in the equal channel angular pressing material while both properties in the swaged microstructure are as stable as in the as-extruded reference.

Effect of Microstructure on the Corrosion Resistance of the AE42 Magnesium Alloy Processed by Rotary Swaging

“…In our study, the microstructure was severely rened by extrusion in the beginning. Similar behavior was found in the ZK60 alloy, where a bimodal microstructure with small grains of 12 µm was achieved by extrusion [9]. Subsequent swaging resulted only in the unication of the grain size distribution similar to this study.…”

“…In the recent years, a positive eect of the grain renement on the corrosion resistance was shown that was achieved mainly by equal channel angular pressure (ECAP) [7,8]. It was shown that grain renement due to the RS could lead to comparable grain size as achieved by ECAP [9]. This technique is very interesting as it enables much faster throughput and lower operating costs than other severe plastic deformation methods.…”

Interrelation of Microstructure and Corrosion Resistance in Biodegradable Magnesium Alloys with Aluminum, Lithium and Rare Earth Additions

“…By optimizing the processing conditions of RS (temperature, feeding velocity) one may attain even ner-grained microstructure than by direct or indirect extrusion [17]. Our earlier study indicated enhanced strength without substantial deterioration of ductility and enhanced fatigue properties in RS ZK60 alloy as compared to ECAP processed material [18].…”

Effect of Rotary Swaging on Microstructure and Mechanical Properties of an AZ31 Magnesium Alloy

“…Oo et al [12] investigated RSW-treated magnesium alloy ZK60. They concluded that despite the achievement of coarser microstructure by RSW than by equal channel angular pressing (ECAP), the yield strength and the ultimate tensile strength of the swaged material were superior.…”