抄録
Adding grain refiners as nucleants is the most common method of refining the grain structure of aluminum casts during the solidification processes. Improvement of grain refining performance can be achieved by severe plastic deformation of grain refiners, since density of heterogeneous nucleation sites could be increased. Another method is use of heterogeneous nucleation sites with smaller disregistry value. In this study, novel refiners for Al cast containing Al_5CuTi_2 intermetallic compound particles with Ll_2 structure or spherical shaped Al_3Ti intermetallic compound particles with DO_<22> structure are fabricated by spark plasma sintering method. The grain refining performance of fabricated refiner was tested using addition of the refiner of 1.2g into molten pure Al of 148.8g. By using the novel refiners, it is found that the grains of Al cast are refined. In this way, these intermetallic compound particles with smaller disregistry value can become favorable heterogeneous nucleation sites for Al cast. Using heterogeneous nucleation sites with lower disregistry value, therefore, one can obtain finer grained Al cast with higher mechanical properties.
