CAJ | 학술논문

为研究轧制钨在氦粒子流与高热流协同作用下的表面形貌演化过程，利用德国马普等离子体物理研究所的 GLADIS 设备对轧制钨板进行了氦源高热流加载实验。结果表明，样品温度对损伤形貌影响显著：低温加载时逐渐发生表面起泡及气泡破裂，且较大尺寸气泡集中分布在近<001>取向区域；高温加载时观察到多孔/珊瑚状结构；中温加载时则呈现出两种损伤形貌的混合。研究认为，表面损伤形貌的形成由表面起泡和珊瑚状结构演化两个过程共同控制。样品温度影响氦在钨中的扩散，从而影响两者的相对强弱，得到不同的损伤形貌。研究发现，辐照剂量的增加也会使得损伤形貌最终向多孔/珊瑚状结构转化。
위연구알제오재양입자류여고열류협동작용하적표면형모연화과정，이용덕국마보등리자체물리연구소적 GLADIS 설비대알제오판진행료양원고열류가재실험。결과표명，양품온도대손상형모영향현저：저온가재시축점발생표면기포급기포파렬，차교대척촌기포집중분포재근<001>취향구역；고온가재시관찰도다공/산호상결구；중온가재시칙정현출량충손상형모적혼합。연구인위，표면손상형모적형성유표면기포화산호상결구연화량개과정공동공제。양품온도영향양재오중적확산，종이영향량자적상대강약，득도불동적손상형모。연구발현，복조제량적증가야회사득손상형모최종향다공/산호상결구전화。
Background: Tungsten (W) is a promising candidate for future use in fusion reactors as plasma facing material. During operation it will be exposed to both particle irradiation and high heat flux (HHF) loads. Particle irradiation, especially helium (He), is expected to cause significant surface modifications of W, might leading to performance degradation. The effect of heat loading can accelerate such surface damage. Therefore, the performance of W under the combined action of both heat and particle fluxes has to be investigated in more detail.Purpose:The aim is to investigate the surface modifications of rolled W during exposure to combined heating and He particle flux depending on surface temperature, He flux and fluence.Methods: The He-flux/heating experiments were performed on rolled W samples using the neutral beam HHF test facility GLADIS at IPP Garching, Germany. HHF loads generated with He atoms of 2.4 MW·m?2 and 9.5 MW·m?2 were used. W samples were adiabatically loaded to peak surface temperatures of ~1000 K, ~2000 K and ~3000 K, close to melting. He fluences increased from about 1×1021m?2 to 6×1022 m?2.Results: During He-loading at a low surface temperature (~1000 K), with increasing fluence, defects appeared in grains first, and then blistering was observed on the sample surface, with many ruptured blisters to form lids and grooves. The largest blisters formed on grains with near <001> surface normal. As fluence was increased continuously, small holes were formed on the surface, and the grooves still existed. However, at intermediate surface temperature (~2000 K), with increasing fluence, the damage morphology changed from a porous structure with blisters,via a porous structure with grooves, to a small coral-like structure. At high surface temperature (~3000 K), an evolution from a porous structure to a coral-like structure with increasing fluence was observed, and the coral-like structure changed little as the increasing of fluence continuously. It is shown that the surface modification of rolled W is dependent on a competitive relationship between the formation of blisters and coral-like structures. To study the behaviour of such He damaged surfaces under fusion relevant transient heat loads, 0.9GW·m?2 Edge Localized Modes (ELMs)-like laser thermal shocks were applied. Local melting was observed on the coral-like structure after thermal shocks.Conclusion: The damage morphology of rolled W changes from blisters with a grain orientation dependence to a porous/coral-like structure with increasing temperature, because at high temperatures the Hen and HenVm (He-vacancy) clusters will be broken up and He will diffuse relatively deeply into the W bulk. This transformation of damage morphology can also be induced by the rise of He fluence.