By Xinyi Li, EDITOR

On July 5, 2019, Nie Jianfeng, a professor at the School of Materials Science and Engineering and the director of Electron Microscopy Center, Chongqing University, together with Prof. Shan Zhiwei at Xi’an Jiaotong University and Prof. Li Bin at University of Nevada, Reno, published a research article titled Large Plasticity in Magnesium Mediated by Pyramidal Dislocations on Science, an internationally top-level academic journal. Prof. Nie is a co-corresponding author, with Chongqing University as his affiliation. It was the first time that the University had published a Science thesis as a corresponding affiliation. The study provides critical experimental data for the theory of plastic deformation of magnesium and also brings new inspiration for the development of high-plasticity magnesium alloy.

A professor at Chongqing University published the study result on Science, which inspires the development of high-plasticity magnesium alloy

Science is dedicated to reporting global significant original scientific results. It is one of the most influential, authoritative, and cutting-edge science journals in the world. The impact factor of the journal reached up to 41.058 in 2018.

What is this article in Science about?

High-strength and lightweight magnesium alloy are widely used in the manufacturing of automobiles, trains, and airplanes as a classical construction material. However, magnesium metal and magnesium alloy have not been applied in large scale due to their low plasticity; since large plastic, deformation is beyond the bearing capacity of the dislocation slip of magnesium <c + a>. Conventionally, the plasticity of magnesium alloy can be enhanced by spiking with some other elements, yet such method is too costly to be promoted in practical application.

High-strength and lightweight magnesium alloy is widely used in the manufacturing of automobiles, trains, and airplanes as a classical construction material

The researchers used in-situ TEM to observe the dislocation slip mechanism of pure magnesium in plastic deformation and discovered that the conical slip system of magnesium <c + a> was able to withstand large plastic deformation. When the magnesium crystalline grains turned into submicron particles, the magnesium showed plasticity far higher than its bulk material.

According to the authors, small crystalline grains often lead to high stress, resulting in movement of more <c + a> slip systems in the magnesium crystals. In this case, the magnesium metal with plasticity deformation from the movement can integrate high strength with plasticity.

In addition, small crystalline grains may restrain deformation of twin crystals. This is a common fracture mechanism in large-grained materials, which is expected to improve the ductility of magnesium as well as other metal and alloy.

Source: CQNews