钨涂层面对等离子体材料损伤演变行为研究

Damage Evolution of Tungsten as Plasma Facing Material for Fusion Device

摘要:

利用等离子体喷涂技术制备了钨涂层面对等离子体材料,并对涂层基本性能进行了表征,主要包括气孔率,相对密度,结合强度,热导率,硬度分布,进而研究主动水冷钨涂层在热负荷服役条件下损伤演变行为。研究发现,直接水冷钨涂层内部层与层之间的开裂、分层是涂层失效的原因,损伤演变过程为柱状晶体再结晶并长大、层间微裂纹出现、裂纹扩展和气孔出现、最后材料分层、失效。间接水冷钨材料的热负荷性能受到很大限制,且疲劳性能降低,失效形式是涂层开裂或脱落,甚至铜基体整体熔化。

Abstract:

Tungsten (W) coating plasma facing material (PFM) was fabricated on the copper (Cu) substrate by means of plasma spraying technolgoy, and it was analysed that the coating porosity, the theoretical density, the bonding strength between tungsten coating and copper substract, the thermal conductivity, the Vickers micro-hardness distribution of tungsten coating. And it was discussed in detail that the damage evolution of tungsten coatings with both of the direct and in-direct cooling condition. The results indicated that the failure reason of W PFM with the direct cooling was the delamination between the lamellar layers, not the surface damage. The damage evolution of W PFM was as follows: the columnar crystals growing up, micro-cracks between the lamellar layers, then the lamellar layer delamination and W PFM failure. But under the indirect cooling, the heat flux performance of W PFM was limited to 7.5MW/m2, not the 10MW/m2 of the direct cooling W coating, and the main failure behaviors were W coating detachment from Cu substrate, which was induced by Cu melting.