| Popis: |
The microstructure and tensile properties of TiB2particles reinforced A356 composite materials at different cooling rates are investigated. Experimental results show that the composition of the alloy solidification ,eutectic silicon content , morphology and size have undergone significant changes while the cooling rate increased: On one hand, α-phase grains significantly reduced, by a 50 μm average grain size refinement to 1~5μm with the evolution from coarse dendritic to rosette dendritic, or even spherical evolution; On the other hand, eutectic Si content increases, and diameter, aspect ratio also showed a decreasing trend, while the circularity is gradually increasing. Meanwhile, with the increasing of cooling rate, the particle distribution of TiB2/A356 particle reinforced composite materials can be optimized. Particle aggregation is reduced, as a result TiB2particles’ reinforcement is more obvious, and the tensile fracture shows the obvious characteristics of ductile fracture. |
