Aluminum matrix composites based on preceramic-polymer-bonded SiC preforms
Aluminum matrix composites based on preceramic-polymer-bonded SiC preforms
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DOI：
10.1016/j.compscitech.2007.01.001
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发表时间：
2007-09
影响因子：
9.1
通讯作者：
M. Thünemann;O. Beffort;S. Kleiner;U. Vogt
中科院分区：
文献类型：
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作者：
M. Thünemann;O. Beffort;S. Kleiner;U. Vogt
以聚甲基硅氧烷（PMS）为粘结剂制备了用于铝熔体压力浸渗的自支撑SiC预制体。SiC颗粒通过喷雾干燥用预陶瓷聚合物涂覆;这确保了细而均匀的分布以及粘合剂的高产率。通过温压、固化和热解将经调理的SiC粉末混合物加工成预制体。聚合物含量为1.25重量%赋予预成型件足够的稳定性以能够进行复合加工。使用该程序，制备具有各种SiC颗粒尺寸分布的SiC预制体。SiC含量约为60 vol.%的Al/SiC复合材料通过挤压铸造浸渗获得的材料的四点弯曲强度为500 MPa，杨氏模量为200 GPa。这些值与组成相同但不含粘合剂的复合材料的值相当。因此，它表明，PMS衍生的粘结剂赋予所需的强度的SiC预制体，而不损害所得的Al/SiC复合材料的机械性能。
Polymethylsiloxane (PMS) was used as a binder to make self-supporting SiC preforms for pressurized aluminum melt infiltration. The SiC particles were coated with preceramic polymer by spray drying; this ensured a fine and homogeneous distribution coupled with a high yield of the binder. The conditioned SiC powder mixtures were processed into preforms by warm pressing, curing and pyrolysis. A polymer content of 1.25wt.% conferred sufficient stability to the preforms to enable composite processing. Using this procedure, SiC preforms with various SiC particle size distributions were prepared. The resulting Al/SiC composites with SiC contents of about 60vol.% obtained by squeeze casting infiltration exhibit a 4-point bending strength of ∼500MPa and Young’s moduli of ∼200GPa. These values are comparable to those of compositionally identical, but binder-free composites. It is thus shown that the PMS-derived binder confers the desired strength to the SiC preforms without impairing the mechanical properties of the resulting Al/SiC composites.