A Study of the Superplasticity of Aluminium LF6&LY12 and an Estimation of Its Plastic Potentiality
Chen Puquan Yang Jinfeng Zhang Nenzhi (Harbin Institute of Technology)
After being pre-processed by rolling and rolling-annealing, two aluminium alloys LF6 and LY12, gain the superplasticity, and under the optimum deformation conditions their elongations in rolling state are the highest: δ=228％, σ=0.25 kgf/mm~2; and δ=226％, σ=2.19 kgf/mm~2 respectively. The grains of the two alloys in rolling state become equiaxed through dynamic recrystallization. The prime reason why the two alloys specimens break down too soon is considered due to certain cavities existing in the boundary surfaces between the second phase and the base phase, and these cavities probably join up with each other into a crack. In order to bring all the plastic potentialities of the alloys into full play, the size of the second phase and the distribution should be under control. Hence the alloys are supposed to be particularly pre-processed, and thereby the grains will be refined to a superfine state and in a dispersd distribution. Therefore it is possible to further improve the plasticity of the alloys.