A novel fabrication technology of in situ TiB2/6063Al composites: High energy ball milling and melt in situ reaction

TiB2/6063Al matrix composites are fabricated from Al-TiO2-B2O3 system by the technology combining high energy ball milling with melt in situ reaction. The microstructure and tensile properties of the composites are investigated by XRD, SEM, EDS, TEM and electronic tensile testing. The results indicate that high energy ball milling technology decreases the in situ reaction temperature and shortens the reaction time for Al-TiO2-B2O3 system in contrast with the conventional melt in situ synthesis. The morphology of in situ TiB2 particles is exhibited in irregular shape or nearly circular shape, and the average size of the particles is less than 700 nm, thereinto the minimum size is approximately 200 nm. In addition, the morphology and size of the reinforced particles are affected by the time of ball milling and in situ reaction. TEM images indicate that the interface between 6063Al matrix and TiB2 particles is clear and no interfacial outgrowth is observed. Tensile testing results show that the as-cast TiB2/6063Al composites exhibit a much higher strength, reaching 191 MPa, which is 1.23 times as high as the as-cast 6063Al matrix. Besides, the tensile fracture surface of the composites displays the dimple-fracture character.