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提高了Cu含量的核反应堆压力容器(RPV)模拟钢经过880℃水淬和660℃调质处理后,在370℃时效6000 h,利用HRTEM,EDS和原子探针层析(APT)方法研究了纳米富Cu相的析出过程和晶体结构演化.观察到Cu原子在α-Fe基体的{110}晶面上以3层为周期发生偏聚,并产生了很大的内应力使晶格发生畸变,这是富Cu相析出时的形核过程;随着Cu含量的增加和富Cu区的扩大,内应力也随着增大,富Cu区沿着α-Fe基体的{110}晶面发生切变,形成了ABC/BCA/CAB/ABC排列的多孪晶9R结构;Cu含量继续增加,富Cu相最终转变为fcc结构.富Cu相的尺寸在1-8nm范围内,数量密度为0.71×10~(23)m~(-3).富Cu相中还含有3%- 8%(质量分数)的Ni和Mn.并且在相界面上发生偏聚,从而抑制了富Cu相的长大.
After being quenched at 880 ℃ and quenched at 660 ℃ for 6 hours, the RPV simulated steel with elevated Cu content was aged at 370 ℃ for 6,000 h. The effects of nano-scale (HRTEM), EDS and atomic probe spectroscopy (APT) Precipitation process and crystal structure evolution of the Cu-rich phase. It is observed that the Cu atom undergoes segregation on the {110} crystal plane of the α-Fe matrix in a three-layer cycle and generates a large internal stress that distorts the lattice, This is the nucleation process when the Cu-rich phase is precipitated. With the increase of Cu content and the expansion of the Cu-rich region, the internal stress also increases. The Cu-rich region along the {110} crystal plane of the α-Fe matrix The multi-twins 9R structure with ABC / BCA / CAB / ABC arrangement was formed, the Cu content continued to increase, and the Cu-rich phase finally transformed into the fcc structure.The size of the Cu-rich phase was in the range of 1-8 nm and the number density was 0.71 × 10 ~ (23) m ~ (-3) .The Cu-rich phase also contains 3% -8% (mass fraction) Ni and Mn, and segregation occurs at the phase interface, thus inhibiting the growth of the Cu-rich phase .