Abstract Scope |
It is well known that Mg has a typical close packed hexagonal structure with few movable slip systems. Compared with aluminum alloys and steels, low plasticity and poor formability of magnesium alloys seriously restricts their wide application. How to improve the plasticity without damaging strength or vice versa has become a research hotspot and focus for development of new types of magnesium alloys in the world. In the past decade, Chongqing University and other units have done a lot of work in the development of high plasticity magnesium alloy, and proposed an alloy design theory of "solid solution strengthening and plasticizing (SSSD)". It is found that the solid solution of some specific atoms in magnesium can not only improve the strength by hindering the slip of basal plane dislocation, but also improve the plasticity by narrowing the slip resistance gap between the basal plane and the non-basal plane and thus promote the activation of non-basal slip. As a result, both strength and plasticity of the magnesium alloy are improved simultaneously. The development of SSSD theory provided a new way to balance and optimize the strength and plasticity of magnesium alloys in the past ten years. Based on this theory, Chongqing University has developed a variety of new high plasticity magnesium alloys, of which more than 10 alloys have been listed in the National Standard or International Standard. The elongation of ultra-high plasticity magnesium alloy can reach to over 65%, and the elongation of ultra-high strength wrought magnesium alloy with σ b > 500MPa can reach to more than 10%. |