HEAT TREATMENTS OF DIFFERENT MAGNESIUM ALLOYS

The primary use of magnesium and magnesium alloys is in aeronautical and automotive industry because of their favorable combination of tensile strength 160 to 365 MPa, elastic modulus (45 GPa), and low density (1 740 kg/m(3)). The properties of the magnesium alloys can be optimized by changing chemical composition of alloys, casting conditions and/or by applying different heat treatments. The selected type of heat treatment depends on the alloy composition and state (cast or wrought), but also on the anticipated service conditions. The basic types of thermal treating processes that can be applied to magnesium alloys are: solution heat treatment, precipitation or aging, and annealing. In addition, two other treatments can be use: stabilizing and stress-relieving. Heat treatment improves strength and hardness and solution heat treatment can lead to maximum toughness. The present paper investigates the influence of heat treatment on AZ80 and ZK60 magnesium alloys and AZ80 and ZK60 magnesium alloys modified by addition of rare-earth elements (REE).