Distribution of TiB_2 Particles and Its Influence on the Primary Si in TiB_2 / A390 Composite

摘要

The hypereutectic Al - Si matrix composite reinforced with TiB_2 particles was successfully fabricated using arnmelt reaction method. The size of TiB_2 particles in the composite is about 0. 5 ～1.0 μm. Some TiB_2 particles are engulfed byrnthe primary Si while the others are mainly pushed to the phase boundaries during solidification. It is believed that highrnconcentrations of TiB_2 particles decreased the size of primary Si and made it less angular. Furthermore, compared with thernmatrix alloy, the ultimate tensile strength of the composite is increased by 8. 8% at 300℃.