双连续TiB2-Cu基发汗陶瓷复合材料抗烧蚀行为

Ablation-Resistance Behavior of Sweat Cooling TiB2-Cn Matrix Interpenetrating Phase Composites

摘要:

用粉末烧结结合自发浸渗法制备高体积TiB2含量（～83％）的双连续TiB2／Cu基复合材料。利用扫描电镜（SEM）和电子探针（EPMA）分析了试验材料烧蚀前后微观组织形貌。用等离子火炬电弧加热器对材料表面瞬时加热来考察复合材料的抗热冲击和抗烧蚀行为。结果表明：材料在电弧加热和冷却过程中没有出现崩裂现象，材料表面也没有裂纹产生，说明该材料具有良好的抗热冲击性能；微观组织分析表明，金属Cu相在材料烧蚀区-过渡区-基体区存在明显的梯度分布，靠近烧蚀区没有检测到金属相的存在，说明在高温下金属起到了“发汗冷却”作用，烧蚀机理为金属相的发汗冷却、化学烧蚀和机械剥蚀。

Abstract:

TiB2/Cu matrix Interpenetrating phase composites (IPCs) with high ceramic content (~vol.83%) were prepared adopting high temperature sintering and subsequently melt-infiltration. The morphologies and microstructures of TiB2/Cu IPCs before and after thermal ablation were studied by SEM and EPMA. The thermal shock behavior and ablation-resistance of TiB2/Cu IPCs were investigated using plasma arc heating. The results showed that no crack was found on the ablated surface during the process of instantaneous heating and cooling, which revealed that TiB2/Cu IPCs have a good thermal shock resistance. Melt Cu phase presented obviously a gradual distribution among the ablation zone, transition zone and matrix zone, and no metal phase was detected near the ablation zone, it means that the melt play a role of sweat cooling during elevated temperature. The ablation-resistance mechanisms mainly include sweat cooling, chemical ablation and mechanical denudation.