用三维原子探针研究压力容器模拟钢中富铜原子团簇的析出

用三维原子探针（3DAP）和热时效处理方法研究压力容器模拟钢中富铜原子团簇的析出过程.提高了Cu含量的压力容器模拟钢样品经过880 ℃加热淬火后，在400和500 ℃进行了不同时间的时效处理，显微硬度测试结果表明，在400和500 ℃时效的过程中硬度峰值分别出现在100和5 h.3DAP分析结果显示，样品在400 ℃分别时效100，150和300 h后，富铜原子团簇的数量密度是递增的，从1.5×10²³ m^-3增加到6.2×10²³m^-3，但富铜原子团簇的长大非常缓慢，团簇的最大等效直径只从2 nm增大到了3.5 nm，团簇中的Cu原子数分数 x 为20%，还含有Mn和Ni，并且观察到Mn和Ni在团簇和基体金属的界面处发生明显的富集.

3D Atom Probe Characterization of Precipitation of Cu-rich Clusters in Pressure Vessel Model Steel

Three-dimensional atom probe (3DAP) and thermal aged method were used to characterize precipitation of Cu-rich clusters in pressure vessel model steel. Pressure vessel model steel specimens were quenched at 880 °C , then aged at 400 °C and 500 °C for different time. The results of hardness test show that peak hardness reached for 100 h aged at 400 °C and 5 h aged at 500 °C, respectively. Analysis results of 3DAP indicate that the number density of Cu-rich clusters increases from 1.5×10²³ m^-3 to 6.2×10²³m^-3, and equivalent diameter of the biggest clusters increases from 2 nm to 3.5 nm after aging 100 h and 300 h at 400 °C . It shows that the growth of Cu-rich clusters is very slow. The content of Cu in Cu-rich clusters is about 20%. Both Mn and Ni atoms are also segregated in Cu-rich clusters and distribution riched at the α Fe matrix/clusters interfaces.