钨面对等离子体材料表面喷丸强化性能分析

Surface performance analysis of tungsten plasma facing material by shot peening technology

核聚变面对等离子体材料表面损伤、失效是其服役寿命的主要影响因素,利用喷丸技术增强钨面对等离子体材料表面性能。以纯钨为被喷丸强化材料,选择0.5 mm不锈钢丸料,在0.4 MPa喷丸压力、100 mm喷丸距离的喷丸参数下,研究不同喷丸时间(30,60,120,240 s)对钨材料表面增强效果,主要包括微观组织形貌和粗糙度、表面硬度及其分布、表面残余应力等。结果显示喷丸对钨表面造成损伤,喷丸弹坑直径约20μm;表面粗糙度较原试样有所提高,但增加幅度不明显,不影响钨作为面对等离子体材料的性能;钨表面硬度从原试样的362HV_(0.2)提升到480HV_(0.2),提升幅度达31%,硬化区厚度约40~50μm;表面残余压应力提高到800 MPa,是原试样的5.9倍。喷丸技术能有效增强钨面对等离子材料的表面强度,提高钨疲劳性能,延长服役寿命。

The main influence factors on the service life of plasma facing materials for fusion device are the surface damage and failure.Shot peening technology is used to strengthen the surface performances of tungsten plasma facing materials.The shot peening parameters were as follows:stainless shot with the diameter of 0.5 mm,shot peening pressure of 0.4 MPa,shot peening distance of 100 mm,and the shot peening time of 30,60,120 and 240 s.The surface strengthening effects of tungsten were studied in detail,which included micro-morphology,surface roughness,surface hardness and its distribution from the shot peening surface,and surface residual compressive stress.After shot peening,no damage was found on the tungsten surface,and the diameter of the diameter of the shot peening crater was about 20μm.The tungsten surface roughness was increased compared with the original sample.But the increment is unobvious,and it does not affect the performances of tungsten as plasma facing material.The surface hardness increment of 31%was obtained from about 480 HV _(0.2) from 362 HV _(0.2) for the original sample,and the thickness of the hardened zone is about 40-50μm.The surface residual compressive stress is increased to 800 MPa,which is 5.9 times that of the original tungsten.Therefore,shot peening technology can effectively enhance the surface strength of tungsten plasma facing material,improve the fatigue performance of tungsten and prolong the service lifetime.