Deformation behavior and controlling mechanisms for plastic flow of magnesium and magnesium alloy

Deformation behavior of pure Mg and Mg alloy were studied in the temperature range of 423 to 773 K and at strain rates of 10(-4)-10(-2)s(-1). Three temperature regions can be categorized both in Mg and Mg alloy. The deformation behavior in Mg can be described by an exponantional law at temperatures below 523 K. At the higher temperatures a power law of deformation is valid with the stress exponent close to n = 7 in the intermediate (523-623 K) and 2.2 in the high (673-773 K) temperature ranges. The alloying of Mg with elements such as Zn changes the phenomenology of plastic deformation. An exponantional law is operative at temperatures below 473 K. At above 473 K deformation obeys a power law. The stress exponent is close to n = 7 at intermediate temperatures (473-523 K) and 5 in the high temperature range. An analysis of experimental results shows that alloying changes the controlling mechanisms of plastic deformation and so leads to different deformation behavior in pure Mg and Mg alloy that can be associated with decreasing stacking fault energy (SFE) in Mg alloy. The effect of SFE on the mechanisms of plastic deformation when alloying Mg is discussed.