Vacuum plasma spraying of functionally graded tungsten/EUROFER97 coatings for fusion applications
Vacuum plasma spraying of functionally graded tungsten/EUROFER97 coatings for fusion applications
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DOI：
10.1016/j.fusengdes.2018.06.006
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发表时间：
2018-08
影响因子：
1.7
通讯作者：
R. Vaßen;Karl-Heinz Rauwald;O. Guillon;J. Aktaa;T. Weber;H. C. Back;D. Qu;J. Gibmeier
中科院分区：
文献类型：
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作者：
R. Vaßen;Karl-Heinz Rauwald;O. Guillon;J. Aktaa;T. Weber;H. C. Back;D. Qu;J. Gibmeier
作为未来聚变发电厂的结构材料，可以使用如EUROFER97的低活化铁素体马氏体钢。不幸的是，等离子体与钢的相互作用将导致有限的寿命，因此研究了保护层。钨是一种优秀的保护材料，因为它具有低溅射、高熔点和低活化的独特性能。然而，由于钨和EUROFER97材料的热物理性能不匹配，会导致材料产生较大的应力甚至失效，采用功能梯度材料（FGM）是解决这一问题的一种可能途径。本文将描述这些功能梯度材料的真空等离子喷涂制造和他们的表征。首先，使用两条不同的进料线来生产涂层。一个主要的问题在于钨和钢的熔点不同。因此，必须调整粒度分布，以在喷涂过程中实现两种材料的充分熔融。在第二步骤中，优化进料速率以在梯度结构中获得所需量的钨和钢相。在热喷涂过程中，梯度不能连续地形成，但是必须以逐步的方式施加。在这项调查中，3和5个不同浓度的样品（不包括纯钢和钨部分）已经生产。这些层的微观结构进行了研究。此外，硬度进行了测量，并通过钻孔法确定了残余应力状态。
As structural materials for future fusion power plants, reduced activation ferritic martensitic steels as EUROFER97 can be used. Unfortunately, the interaction of the plasma with the steel would result in a limited lifetime, so protective layers are investigated. An excellent protective material is tungsten, as it shows unique properties with respect to low sputtering, high melting points and low activation. However, the mismatch of thermo-physical properties between tungsten and EUROFER97 can lead to large stress levels and even failure.A possible way to overcome this problem is the use of functionally graded material (FGM). The paper will describe the manufacture of these FGMs by vacuum plasma spraying and their characterization. First of all, two different feeding lines have been used to produce the coatings. A major problem lies in different melting points of tungsten and steel. So the particle size distribution has to be adjusted to achieve sufficient melting of both materials during the spray process. In a second step, the feeding rates were optimized to obtain the wanted amount of tungsten and steel phases in the graded structures. In a thermal spray process, the gradient cannot be made continuously, however it has to be applied in a step-wise manner. In this investigation, samples with 3 and 5 different concentrations (excluding the pure steel and tungsten part) have been produced. The microstructures of these layers have been investigated. In addition, hardness was measured and the residual stress state was determined by the hole drilling method.