Formation mechanism of the discontinuous dendrite structure in AI-La alloys

Al-La alloy samples with different compositions were prepared by a free solidification method. The results show that the dendrite structure of Al₁₁La₃ in an Al-35% La alloy is discontinuous. For demonstrating the authenticity of this structure, adopting a directional solidification method, Al-35% La alloy samples were prepared at different solidification rates. It is indicated that the dendrite structure of Al₁₁La₃ in the Al-35% La alloy obtained by directional solidification is discontinuous. The effects of composition and solidification rate on the microstructure of Al-La alloys were analyzed, and the formation mechanism of the discontinuous dendrite structure was discussed preliminarily.