Study Of Substitutional Atom Pinning Effect On Magnesium Alloy Deformation Twinning

Magnesium alloy has low density, high specific strength,So it has been applied in the automobile, as well as the aerospace field. But the strength of the magnesium alloy with low plasticity, limits its application. Therefore, in this paper, in order to enhance magnesium alloy as the objective, around substitutional atom of magnesium alloy deformation twin pinning effect research.This work has studied the effect of different content of Zr on grain size of Mg-5Gd-3Y-xZr alloy and optimize the solution treatment of magnesium alloy conditions, the microstructurc and compression properties of Mg-5Gd-3Y-xZr alloys in as-casting and after solution treatment were investigated in the present paper. The results show that with the content of Zr increasing, the grain size of Mg-5Gd-3Y-xZr alloy decreases, and yield strength and compressive strength increase. The relationship between the yield strength and grain size is in line with Hall-Petch equation. The optimal solution treatment condition of Mg-5Gd-3Y, Mg-5Gd-3Y-0.3Zr and Mg-5Gd-3Y-0.6Zr is 520℃×4h,480℃×6h and 450℃×12h, respectively.Study on the effect of solute pinning effect on magnesium alloy twin, the results of the study indicate that the solute element Gd on twin pinning enhancement effect than that of Y, and when the two kinds of solute elements coexisted strengthening effect of high solute elements play a main role. Study the influence of deformation process pinning effect on twinning. High temperature slow deformation twinning, while generating and pinning occurs, increase strength, slightly tapering twin. A number of deformation combined with annealing twins can produce higher density to make the pinning effect to achieve better enhancement effect.Study on the cumulative deformation of pinning enhancement effect, when accumulated large amount of deformation twins produced higher density. Therefore, magnesium alloy deformation twin pinning enhancement effect is more obvious. Studied the annealing time and annealing temperature effect on enhancement of twin bar nail. With increasing annealing time, annealing temperature, the deformation of Mg-10Gd-3Y-0.3Zr magnesium alloy strength increasing. However, if the annealing time is too long at low temperature, the recovery causes the slight decrease in strength. At high temperature, the ordered segregation of solute atoms to the deformation twin boundary will become unstable, and then the strength rapidly decreases with increasing temperature.