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采用调质处理后热时效模拟方法,用原子探针层析成像技术研究了核反应堆压力容器模拟钢中富铜纳米团簇的析出过程.模拟钢经880℃加热水淬,660℃高温回火调质处理,并经400℃时效处理1000 h后基体中析出了富铜纳米团簇.使用MSEM(maximum separation envelope method)方法重点研究了富铜纳米团簇在析出早期阶段成分变化规律.结果表明,富铜纳米团簇容易在镍含量较高的位置形核,并随着富铜纳米团簇中铜原子聚集程度的增加,纳米团簇中心处铜含量逐渐增加,镍含量逐渐减少;在纳米团簇与α--Fe基体界面处,镍和锰含量逐渐增加,形成了富镍和富锰包裹富铜纳米团簇的结构.结合实验结果讨论了压力容器钢中合金元素镍及杂质元素磷会增加中子辐照脆化敏感性的原因.
The thermal aging simulation method after quenching and tempering treatment was used to study the precipitation process of copper-rich nanoclusters in simulated pressure vessel of nuclear reactor by atomic probe tomography.The simulated steel was quenched by heating at 880 ℃ and tempering at 660 ℃ , And the copper-rich nanoclusters were precipitated in the matrix after aging at 400 ℃ for 1000 h.The composition of the copper-rich nanoclusters in the early stage of precipitation was mainly studied by the maximum separation envelope method (MSEM) Copper nanoclusters tend to nucleate at the higher nickel content. With the increase of copper atoms in the copper-rich nanoclusters, the copper content in the center of the nanoclusters gradually increases and the nickel content decreases gradually. At the interface with α - Fe matrix, the content of Ni and Mn gradually increased, and the structure of Ni - rich and Mn - rich Cu - rich nanoclusters was formed.According to the experimental results, the content of alloying elemental nickel and impurity element phosphorus in pressure vessel steel was increased Neutron radiation embrittlement susceptibility reasons.