无压渗透制备（Al2O3）P／Al复合材料的结构及渗透机理

叙述了无压液态金属（含镁铝合金）渗透法制备Ａｌ２Ｏ３颗粒增强铝基复合材料（Ａｌ２Ｏ３）ｐ／Ａｌ的工艺过程，对（Ａｌ２Ｏ３）ｐ／Ａｌ的微观结构进行了分析，提出了无压渗透机理。分析结果表明，试样渗透完全，（Ａｌ２Ｏ３）ｐ／Ａｌ显微结构致密；在Ａｌ２Ｏ３与Ａｌ的界面处，原位生成ＭｇＡｌ２Ｏ３尖晶石晶体，它使界面结合牢固，对复合材料起到强化作用，镁除与Ａｌ２Ｏ３反应外，其余部分固溶于基体铝中，特定的合金成份及特殊的截留气氛下以及原位反应都有助于改善铝对（Ａｌ２Ｏ３）ｐ的浸润性或产生选择渗透，这样，铝在自发状态下完全渗透入（Ａｌ２Ｏ３）ｐ骨架之中。

Microstructure and Infiltration Mechanism of(Al_2O_3)P/Al Composite Fabricated by a Pressureless Infiltration Process

Pressureless infiltration process for manufacruring Al2O3 particle reinforced (Al2O3)p/Al composite with Mg - containing Al alloy is discribed. By means of metalloscope,EDS, the microstructures of (Al2O3)p/Al were analysed and the pressureless infiltration mechanism is discussed. The results show that the spontaneous penetration is forly prefect and (Al2O3)p/Al has dense microstructure. In the interface of (Al2O3)p/Al, there are MgAl2O4 spinels which are in-situ formed by teaction of Mg and Al2O3; in addition to this, the remaining magnesium is in solid solution with mains alkuminium.The primer infiltration mechanisms are in that the enhanced wetting of molten aluminium to Al2O3 in the given mg-contining Al alloys and the special nitrogenous penetration atmosphere; besides, the reaction of interface can also improve wetting or result in preferred infiltration.