Liquid structure of Al-TM (TM = Fe, Ni) alloys was studied by high temperature X-ray diffractometer. In the structure factor S (Q) of Al- 1.0 at% Fe ally, it is found that there exists a small prepeak at 670 ℃ , implying the medium range order (MRO) structure; the prepeak disappears when the temperature is up to 1400 ℃. For Al-20at% Ni alloy, the prepeak exists in S(Q) when the temperature is lower than 1300 ℃, and it is weakened drastically when the temperature surpasses 1300 ℃. In the same experiment conditions, there is no such prepeak, namely MRO structure in S(Q) of pure Al and Al-12.5at% Si alloy. These results show that there exists not only the short range order (SRO) structure but also MRO structure in the Al-TM melts, and the MRO is correspondent with the tendency of formation of chemical compounds.

Key words: FUSE ELEMENTS, ALUMINIUM ALLOYS, SILICON ALLOYS, NICKEL ALLOYS, XRD