Infiltration Mechanism in SiCp/Aluminum-Matrix Composite Prepared by Nonpressure

摘要

Infiltration of liquid aluminum alloy onto SiC particles requires them to be in wet contact at a high temperature, i.e., wetting angle 0 < 90°. The chemical reaction between these substances also promotes wetting. The calculation shows that the interfacial reaction reduces the contact angle 6 to 66° from more than 120°. It is found that the infiltration process can be roughly divided into the following four steps: (1) gestation, (2) infiltration for high-temperature alloy liquid into the SiC particles, (3) infiltration for high-temperature alloy liquid in tiny pores, and (4) solidification to form composite materials.The time of the gestation period is related to the temperature and the alloy composition. The gestation period of this experiment is approximately 28 minutes. The relationship between the infiltration depth and time is as follows: L = —32.647 + 6.14(t)~2. Other relations are known between infiltration depth and particle size of ceramics, infiltration depth and temperature, critical pressure, ceramic particle size, etc. The solidification contraction between SiC and aluminum alloy vary greatly;;a solidification method of faster cooling followed by slower cooling is thus determined, resulting in a better composite microstructure.