Fabrication of ceramics matrix composite by melt infiltration in situ synthesis and its toughening.

液态铝自发渗透到NiO和TiB_2的粉末混合物中。然后通过3NiO+2Al*Al_2O_3+3Ni的反应原位制备金属Ni分散氧化铝基复合材料，同时原位生成Al_3Ni。在这种情况下，渗铝至少需要18 vol%的TiB_2颗粒。此外，在先前使用的粉末混合物中加入直径约为1-3mm的大氧化铝颗粒并不影响铝熔体的渗透行为，从而显示出良好的结构。与单片氧化铝相比，含如此大的氧化铝颗粒的复合材料和不含这些颗粒的复合材料的抗热冲击性能都更好。将液态铝渗透到Mg_3N_2压制的粉末预制件中，在1473K的氮气气氛下进行2Al+Mg_3N_2*2AIN+3Mg（in Al）的反应，可以制备出58 vol%AIN和42 vol%Al- mg合金的复合材料。将液态铝浸入由BN和Me （Me: Ti或Ta）组成的压制粉末预制体中，通过2Al+Me+ 20亿*MeB_2+2AIN的反应制备（MeB_2+AIN）基分散金属铝的复合材料。

Liquid aluminum spontaneously infiltrated into the powder mixture of NiO and TiB_2. Then the metallic Ni dispersing alumina matrix composite was in situ fabricated by the such reaction as 3NiO+2Al*Al_2O_3+3Ni, though Al_3Ni was also in situ formed. In this case, 18 vol%TiB_2 particles were required at least for the aluminum infiltration. Moreover, the infiltration behavior of aluminum melt didn't be affected by the addition of large alumina particles of about 1-3mm in diameter into the powder mixture used previously, resulting in revealing sound structure.The resistance to the thermal shock both composite containing such large alumina particles and that free from those particles were better, compared with monolithic alumina.Composite of 58 vol%AIN and 42 vol%Al-Mg alloy could be fabricated by infiltrating the liquid aluminum into the pressed powder preform of Mg_3N_2, and by the reaction such as 2Al+Mg_3N_2*2AIN+3Mg(in Al) at 1473K under nitrogen atmosphere.By infiltrating liquid aluminum into the pressed powder preform composed of BN and Me (Me : Ti or Ta), (MeB_2+AIN) matrix composite dispersing metallic aluminum could be fabricated through the reaction such as 2Al+Me+2BN*MeB_2+2AIN.