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不锈钢结构材料中Cu纳米团簇是导致核反应堆压力容器钢脆化的主要原因之一。本文用扫描电子显微镜(SEM)和正电子湮没谱学(PAT)研究材料中的纳米Cu颗粒以及微观缺陷经热处理后的回复过程。PAT测量结果表明,Fe-1.5wt%Cu合金在1 173 K高真空退火处理后,主要缺陷得以回复,合金中存在Cu纳米颗粒且能吸引并捕获热化后的局域态正电子。SEM对不同温度退火样品的微观结构进行表征,结果表明,随着退火温度的升高,合金中Cu纳米颗粒的浓度逐渐降低。1473 K退火,SEM未观测到明显的Cu纳米颗粒,而多普勒展宽能谱的W参数表明合金中仍存在微小Cu纳米颗粒。
Cu nanoclusters in stainless steel are one of the main reasons leading to embrittlement of pressure vessels in nuclear reactors. In this paper, scanning electron microscopy (SEM) and positron annihilation spectroscopy (PAT) were used to study the recovery process of nanocrystalline Cu particles and microscopic defects in the material after heat treatment. The results of PAT measurement showed that the main defects were recovered after the high-vacuum anneal of Fe-1.5wt% Cu alloy at 1 173 K, and Cu nanoparticles were present in the alloy and could attract and capture the localized positron positron after heating. The microstructure of samples annealed at different temperatures was characterized by SEM. The results showed that the concentration of Cu nanoparticles gradually decreased with the increase of annealing temperature. At 1473 K annealing, no obvious Cu nanoparticles were observed by SEM, while the W parameters of Doppler spectrum showed that Cu nanoparticles still existed in the alloy.