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以尿素为造孔剂,利用自蔓延高温合成技术制备了多孔TiC/FeAl复合材料,主要考察了Ti-C含量(质量分数15wt%~35wt%)对多孔材料孔型结构和压缩性能的影响。当Ti-C含量不高于25wt%时,多孔TiC/FeAl复合材料由毫米孔和孔壁微孔组成规则的复合孔型结构。相互连通的毫米孔产生于尿素颗粒的挥发和液相迁移;微孔尺寸10~50μm,产生于Fe-Al-Ti-C粉末的自蔓延过程,孔径随Ti-C含量的增加而增大。通过调整尿素的体积分数,多孔材料的孔隙率可控制在56.64%~85.35%。当Ti-C含量不高于25wt%时,多孔材料的抗压强度随Ti-C含量的增加而增大。当Ti-C含量高于25wt%时,多孔材料壁面微孔形状很不规则,且抗压强度下降。孔隙率约64.3%时,多孔Fe-Al金属间化合物和TiC/FeAl复合材料(25wt%Ti-C)的抗压强度分别为20.03MPa和66.68MPa,对应的应变值分别为4.77%和8.21%。另外,多孔TiC/FeAl复合材料的压缩性能可用Gibson-Ashby模型来解释。
Porous TiC / FeAl composites were prepared by self-propagating high-temperature synthesis with urea as pore-forming agent. The effects of Ti-C content (15wt% ~ 35wt%) on pore structure and compressive properties of porous materials were investigated. When the content of Ti-C is not higher than 25wt%, the porous TiC / FeAl composites consist of the regular composite pore structure of the micropores and the pores of the pores. The interconnected mm pores are generated by the volatilization of urea particles and the liquid phase migration. The pore size is 10-50 μm and results from the self-propagating process of Fe-Al-Ti-C powders. The pore size increases with increasing Ti-C content. By adjusting the volume fraction of urea, the porosity of porous materials can be controlled at 56.64% ~ 85.35%. When Ti-C content is not higher than 25wt%, the compressive strength of porous materials increases with the increase of Ti-C content. When Ti-C content is higher than 25wt%, the micropore shape of the porous material wall surface is irregular, and the compressive strength decreases. When the porosity is about 64.3%, the compressive strength of porous Fe-Al intermetallic compound and TiC / FeAl composite (25wt% Ti-C) are 20.03MPa and 66.68MPa respectively, the corresponding strain values are 4.77% and 8.21% . In addition, the compressive properties of porous TiC / FeAl composites can be explained by the Gibson-Ashby model.