正电子湮没技术探讨铜对微合金钢缺陷的影响

Discussion on the effect of trace copper on micro-alloying steel defects by positron annihilation techniques

采用正电子湮没寿命和多普勒展宽谱探讨了含铜超低碳微合金钢在连续冷却过程中,微量元素铜对其缺陷的影响。结果表明:从1 150℃以5℃/s冷速到850℃的过程中,超低碳微合金钢中的主要缺陷为单空位和位错;铜元素不仅显著影响了微合金钢中缺陷数量随温度的变化规律,并且降低了单空位和位错缺陷的总数量;不含铜微合金钢中缺陷数量随温度的降低先增大再减小,且在1 000℃时达到最大值;含铜微合金钢中缺陷数量随温度的降低基本保持不变。

Positron annihilation lifetime（PAL） and Doppler broadening spectra have been applied to discuss the effect of trace copper on the defects of ultra-low carbon micro-alloy steel during continuous cooling process. The results show that in the process of cooling from 1 150 ℃ to 850 ℃ at 5 ℃/s, the main defects in ultra-low carbon micro-alloy steel are dislocations and single vacancies. The trace copper not only significantly affects the change of defect number with temperatures, but also decreases the sum of the number of dislocations and single vacancies. During the cooling process, the number of defects in copper-free micro-alloying steel increases first, then decreases and reaches its maximum at 1 000 ℃. The number of defects in copper- bearing micro- alloying steel remains invariable with the drop of temperature in the whole cooling process.