Melt Infiltration Ability and Microstructural Evolution of Fe40Al/TiC Composites System
会议名称：《第十届国际制造工程与管理会议》
会议日期：2002年
学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）]
摘 要：Pressureless melt infiltration is an economic route for preparation of high-density ceramic/melt composites. In this study, the Fe40Al iron aluminide intermetallic, a low cost material of excellent oxidation and corrosion resistance, was used as binder for fabricating Fe40Al/TiC composites by pressureless melt infiltration. The wetting ability of liquid Fe40Al in porous TiC preform was studied by in-situ monitoring the melting and infiltration process. The infiltration ability was investigated by observing the distance of liquid Fe40Al intrusion in porous TiC pre-forms at different infiltration temperatures and times by using optical microscope. Porous TiC per-forms with density of 60% - 88%TD (theoretical density), prepared under pre-defined sintering temperature cycles, were used for fabricating Fe40Al/TiC composites in the range of 12% - 40% metal content by volume. Almost full dense Fe40Al/TiC composites were successfully fabricated by this technique. Liquid Fe40Al exhibited excellent infiltration ability, the distance of complete intrusion of liquid Fe40Al in the TiC sintered pre-form with density of 88%TD was over 7 mm after 5 min at the infiltration temperature of 1 450 ℃.Microstructural observation by SEM and TEM also showed that liquid Fe40Al filled the very narrow gaps among TiC particles, the interfaces of TiC particles and Fe40Al plastic ligaments being metallurgical bonded. TEM revealed that high density of dislocations formed in Fe40Al ligaments during solidification, which favor the mechanical properties. Ti decomposed from TiC particles and dissolved into Fe40Al during infiltration. According to the compositional analysis of TEM-EDS, the concentration of Ti in Fe40Al ranges at 1at% - 4at% depending on composite fabricating conditions and the distance from the measuring point to the closest TiC particles. XRD analysis indicated that the composites were composed of two phases, the original TiC and Fe0.4Al0.6 intermetallic. No new phase formed during in