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将Cu含量高于实际核反应堆压力容器(RPV)钢的模拟钢在880℃水淬后,在660℃进行调质处理,然后在370℃时效不同时间,采用TEM,原子探针层析法(APT)和冲击实验对其进行研究.结果表明,时效1150 h后,富Cu团簇的析出仍处于形核阶段,对韧-脆转变温度(DBTT)没有明显的影响;时效3000 h后,试样中析出了平均尺寸为1.5 nm的富Cu团簇,主要分布在位错线上,数量密度达到4.2×10~(22)m~(-3),DBTT由调质处理后的-100℃升高至-60℃;时效13200 h后,富Cu团簇略有长大,平均尺寸达到2.4 nm,团簇的数量密度与时效3000 h的试样处于相同数量级,DBTT升高至-45℃.采用热时效方法使富Cu团簇析出后,DBTT只提高了55℃,没有中子辐照引起的那样显著,这不仅是因为富Cu团簇的数量密度低,基体中没有中子辐照产生的晶体缺陷也是重要的原因.
The simulated steel with higher Cu content than the actual reactor pressure vessel (RPV) steel was quenched at 880 ℃ and quenched at 660 ℃. Then the samples were tempered at 370 ℃ for different time. TEM, atomic probe spectroscopy (APT ) And impact experiments were carried out.The results show that the precipitation of Cu-rich clusters is still in the nucleation stage after 1150 h aging, and has no obvious effect on the ductile-brittle transition temperature (DBTT) Cu clusters with an average size of 1.5 nm were precipitated, which mainly distributed on the dislocation line with the number density of 4.2 × 10 ~ (22) m ~ (-3). DBTT increased from -100 ℃ after quenching and tempering Up to -60 ℃. After aging for 13200 h, the Cu-rich clusters grew slightly, with an average size of 2.4 nm. The number density of clusters was in the same order of magnitude as that of the samples aged for 3000 h, and DBTT increased to -45 ℃. After the Cu-rich clusters were precipitated by the thermal aging method, the DBTT increased only by 55 ° C, not as significant as that caused by the neutron irradiation, not only because of the low number density of the Cu-rich clusters and the absence of neutron irradiation in the matrix The crystal defects are also important reasons.