Investigation of mechanical properties and corrosion resistance of AZ63 magnesium alloys after cryogenic process

Magnesium is the lightest of all design metals. It is as light as a plastic material and at the same time hard as metal. High specific toughness and hardness, good workability, coatability and weldability by known methods have become attractive for the industry. The newest metal is magnesium of use our age, is increasing parallel with developments in industry and technology. Due to its lightness, durability and longevity, it is in use for industrial. The use of Mg alloys in automobiles increases fuel efficiency and reduces emissions by reducing vehicle weight. The AZ63 alloy is a cheaper material than other magnesium alloys because it is widely used as a sand-casting anode material, and its tensile strength and elastic modulus are similar to those of the AZ91 alloy used in the automotive, aerospace industry, although the notch impact strength is higher than most magnesium alloys. The easy production of AZ63 alloy by using the casting method makes it attractive to use this alloy because it has similar properties compared to advanced magnesium alloys. Studies have been carried out on the examination of wear, corrosion and mechanical properties of magnesium-aluminum alloys. These studies are usually investigated either by changing the test ambient temperatures or after coating. Although there is not much work in the literature for the AZ63 alloy, the literature on the cryogenic process for the AZ63 alloy is not available. The main limiting factor in the use of magnesium alloys is the low corrosion resistance and the degradation of wear resistance under high loads. For these reasons, especially in the automotive industry, these properties become a problem. The aim of this study is to improve the corrosion resistance of AZ63 magnesium alloys and wear resistance under high loads and to be used in more industrial applications. In this thesis, we compared the improvements in material properties of AZ63 magnesium alloys in the first casting phase, in the homogenization annealing, in the precipitation hardening and in the cryogenic processing, in terms of corrosion resistance and microstructural properties. As the phase distributions in microstructure increased and grain size decreased, the hardness values and elongation values increased. Substantial increase in the corrosion resistance of the material along with the appearance of secondary phases in the microstructure was observed. Key words: Corrosion, Cryogenic, Magnesium, Magnesium alloys, Microstructure.