Grain refining potency of LaB6 on aluminum alloy

Al-LaB6 alloy was successfully prepared by aluminum melt reaction method. Microstructure analysis of this alloy was carried out by field emission scanning electron microscopy (FESEM), Raman spectroscopy and transmission electron microscopy (TEM). It was found that cubic LaB6 particles were highly dispersed in aluminum matrix with a uniform edge length of about 4.5 mu m. Grain refining potency of LaB6 on commercial pure aluminum was also investigated. It was shown that LaB6 could act as an effective and stable nucleation substrate for alpha-Al during solidification process, due to their crystallographic similarity. The coarse grains of commercial pure aluminum were obviously refined to small equiaxed ones by addition of 0.5% Al-5LaB(6) alloy at 720 degrees C.