Al-Ti-B-Er refiner was successfully prepared by CR (contact reaction process),a process based on SHS (self propagating high-temperature synthesis).The microstructure of the alloy was studied by optical microscopy,X-ray diffraction (XRD),scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry.The results showed that Al-Ti-B-Er alloy was composed of α-Al,block-like TiAl3 and flocked TiB2.Compared with Al-Ti-B refiner,formation of TiAlEr compounds,Er modified the mor-phology of TiAl3 phase,and dispersed the TiB2 and TiAl3.An excellent grain refining performance was obtained when adding 1 wt.% Al-Ti-B-Er in Al-10Zn-1.9Mg-1.6Cu-0.12Zr alloy,the average grain size was about 40 μm.The refinement mechanism of Al-Ti-B-Er was also discussed.Er changed the morphology of TiAl3,TiB2 phase,the refiner would be more efficient.The decompo-sition of TiAlEr compounds which released Er refrained the growth of TiAl3 and made TiB2 difficult to aggregate or deposit,there-fore resulted in more particles being efficient nucleation substrate.
