Abstract:

The effects of Zr, Ti and B elements additions on the microstructure evolution of 6061 aluminium alloy were investigated in this article. The microstructure observations show that the addition of Zr, Ti and B elements can effectively refine α-Al from coarse dendrites to fine equiaxed grains. In addition, the result displays that the Zr, Ti and B elements added into 6061 melting can form ternary (Ti_1−x,Zr_x)B₂ compounds, which distribute in the core of α-Al grains or lie in the vicinity of α-Al grain boundaries. Hence, the mechanism of grain refinement can be explained by heterogeneous nuclei theory and restricting growth theory.