| The application of aluminum and aluminum alloy are widely, people more strict on the microstructure and mechanical properties of its products. It is well known that an equiaxed grain structure is in favor of improving mechanical properties, reducing hot tearing, eliminating shrinkage porosity and micro-porosity, and making a uniform distribution of second phases on a fine scale, as well as improving machining ability of castings. At present, the most simple, economical and effective method is to use grain refiner for thinning aluminum and aluminum alloy processing.Al-Ti-B-RE master alloy is an efficient long-term new refiner. Al-5Ti-lB-lRE refiner was prepared by Al-5Ti-lB master alloy doped with LaF3, La-rich RE (rare earth) carbonate and Ce respectively. Study the preparation of Al-Ti-B-RE master alloy and its refining effect on pure aluminum and6063alloy by the rare earth modification, purification, degassing effect and refinement effect of Al-Ti-B master alloy combination.This paper studies the effect of different type and mass fraction of RE on the Second phase particles distributions, shape and micro-hardness in Master Alloy. The microstructure of the alloy was characterized by optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry. The results show the microstructure of Al-Ti-B-RE alloy is composed of a-Al, lath-shaped TiAl3, granular TiB2, and blocky or rim Ti2Al2oCe. The addition of rare earth has the refinement of TiAl3and TiB2intermediate phase certain. Moreover, it prevents aggregation of TiB2intermediate phase. The type of RE has little effect on the microstructure of the Al-Ti-B-RE master alloy, while the different addition of RE has an effect on the microstructure of Al-Ti-B-RE master alloy, then the reasonable addition of RE is put forward.During the experiment of refining, Al-Ti-B-RE alloy was used for grain refinement studies on pure aluminum and6063alloy. By changing the addition amount of Al-Ti-B-RE (0.1wt%,0.2wt%,0.4wt%,0.6wt%and0.8wt%) and the refinement holding time (5min,10min,20min,30min,40min), These variables on the influence of the microstructure and mechanical properties of pure aluminum are investigated. Compared with the refining effect of the domestic Al-Ti-B and imported Al-Ti-B in the same conditions, respectively. Extend the refinement holding time, Al-Ti-B-RE refining agent on the refining effect of pure aluminum recession is not obvious. Al-Ti-B-RE has stronger refining performance and longtime efficiency than Al-Ti-B. The mechanical properties of aluminum improved significantly by aluminum Al-Ti-B-RE refinement. Al-Ti-B-RE also has a prominent refining effect for6063alloy. The Al-Ti-B-RE refinement mechanism are discussed in this paper, based on the existing theory provides a reference and practice basis, to the further development of high performance of Al-Ti-B-RE refiner is of great significance. |
