硼/钇合金化FeAlCr多孔材料的脆性行为及调控机制

FeAlCr intermetallic filter materials, which possess excellent high-temperature strength, outstanding corrosion resistance and favorable economy, have recently been widely applied in the filtration of high-temperature gases from metal metallurgy, coal-fired power generation, coal gasification industries, etc. However, FeAlCr filter material showed a tendency to brittleness during manufacturing and application. Accordingly, this project is proposed to fabricate a new kind of FeAlCr porous materials with low brittleness using Fe/Al/Cr mixed elemental powders with boron (B)/yttrium (Y) addition. The pore formation and componential homogenization can be achieved by step heating method to avoid the occurrence of self-propagating high-temperature synthesis reactions. Researches would be concentrated on the factors affecting the embrittlement behavior of porous FeAlCr alloyed with B/Y. These factors include the thermal vacancy, grain size, spinodal decomposition and carbides precipitation, which can be respectively or synthetically controlled by B/Y alloying. Meanwhile，an optimized heat treatment schedule would be developed to coordinate the effect of B/Y alloying. It is expected that the initial brittleness of porous FeAlCr could be reduced and that the embrittlement caused by intermediate-temperature aging and carbonization could be restrained. The research results would contribute to the understanding of the embrittlement behavior of FeAlCr materials and can serve as the theory guidance for the manufacturing and application of FeAlCr porous materials which can resist the tendency to embrittlement.

FeAlCr金属间化合物滤材具有优异的耐高温、耐腐蚀性和经济性，被广泛应用于冶金、煤电、煤化工等行业的高温气体过滤。针对当前FeAlCr金属间化合物滤材存在的脆性问题以及由此给制造及应用过程造成的困扰，本项目提出在Fe/Al/Cr元素混合粉中掺入硼(B)和钇(Y)元素，通过梯度升温实现非自蔓延燃烧条件下的偏扩散造孔和均匀合金化，可控制备具有低脆性倾向的B-Y复合合金化FeAlCr多孔材料，并主要研究B调控合金热空位、高熔点含Y相抑制晶粒长大以及固溶B-Y抑制调幅分解和碳化物析出等微观机制对材料脆性行为的影响；探索出匹配的热处理工艺，实现与B/Y合金化作用的微观机制相耦合，以降低FeAlCr多孔材料的初始脆性，并抑制中温时效以及碳化导致的脆性倾向。研究结果有望揭示FeAlCr多孔材料的脆性产生机制，并为低脆性倾向FeAlCr多孔材料的制备和应用奠定理论基础。

FeAlCr金属间化合物滤材被广泛应用于冶金、煤电、煤化工等行业的高温气体过滤单元。针对当前FeAlCr金属间化合物滤材存在的脆性及高温性能不足的问题，本项目优化出最优的Al、Cr、B、Y成分范围，研究了添加合金化元素B、Y对多孔材料反应合成过程、力学性能、抗高温氧化、碳化性能的影响。通过第一性原理计算确定了B在FeAl合金中的占位及对合金体系影响机制。通过长时间时效试验研究了高温时效过程FeAlCr多孔材料及B、Y合金化FeAlCr多孔材料微观组织发生的演变以及由此导致的力学性能性能变化，尤其揭示了B在抑制多孔材料晶界内氧化方面的关键作用。通过成分优化，FeAlCr多孔材料室温强度可提升30~50 MPa，延伸率从~2.0%提升至~6.0%，显著改善了使用过程的脆性问题。B-Y合金化显著改善了合金在高温氧化、碳化等氛围中的服役寿命，抑制了由于富铬相析出、表面/晶界氧化等导致的力学性能下降。研究结果提升了FeAl合金滤材的高温服役性能，使其在高温过滤、化工合成气重整、催化部分氧化、燃料电池(SOFC)、气体渗透膜等应用场合展现出更广阔的前景。

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