Si_p/ZA27复合材料在部分重熔过程中的组织演变

Microstructure Evolution of SiZA27 Composites During Partial Remelting

研究了经Zr-P双重变质的Sip/ZA27复合材料在半固态温度475℃部分重熔过程中的组织演变。结果表明,经双重变质的复合材料,组织由发达的树枝晶变为短粗枝晶,初生Si变细小。在加热过程中,短粗枝晶粗化形成少晶界或无晶界的相连组织;随后因共晶组织的熔化造成组织分离,形成相互独立的不规则颗粒;最后由于不规则组织突出部位的熔化,使组织圆整化。在加热初期Si无明显的变化,随着加热时间的延长,Si棱角变得圆整,且有减小的趋势。

Microstructure evolution of Zr and P compound modified Si/ZA27 composites during remelting at 475℃ was observed. The results show that microstructure of the composites modified by Zr and P is converted from developed dendrite into short-coarse dendrite with fine primary Si phase. The interconnected structure with a few or without boundaries is generated due to the growth of short-coarse dendrite, and is further formed irregular independent particle during eutectic phase melting, resulting in the spheroidization of the particles during partial remelting process. With the increase of heating time, the primary Si phase in the microstructure is spherodized with the decrease of Si phase size.