论文部分内容阅读
研究了喷射沉积Al 2 0 %Si及Al 30 %Si合金坯料的显微组织及形成机理。结果表明 ,两种合金的喷射沉积态组织为细小的团块状Si均匀地分布于基体α上 ,没有共晶组织出现。形成该组织特征的机理是由于在沉积阶段凝固过程中合金发生了离异共晶 ,在雾化阶段大的冷却速度下形成的大量Si相核心以及在沉积阶段相对较低的冷却速度为这一过程提供了动力学条件。通过自行设计的沉积阶段凝固的模拟实验 ,对这一机理进行了验证 ;另外 ,还对Si相的形态、尺寸进行了一定的研究
The microstructure and formation mechanism of spray-deposited Al 2 0% Si and Al 30% Si alloy billets were studied. The results show that the as-sprayed microstructures of the two alloys are uniformly distributed on the matrix α as fine agglomerates Si, and no eutectic microstructure appears. The mechanism of the formation of this tissue is due to the fact that the alloy has been subjected to dissimilar eutectic during solidification in the deposition phase, a large number of Si phase nuclei formed at a large cooling rate during the atomization phase, and a relatively low cooling rate during the deposition phase. Kinetic conditions are provided. This mechanism was verified by a self-designed simulation experiment of solidification during the depositional phase. In addition, the morphology and size of the Si phase were also studied