Study of phase transformation and mechanical properties evolution of duplex stainless steels after long term thermal ageing (>20 years)
Study of phase transformation and mechanical properties evolution of duplex stainless steels after long term thermal ageing (>20 years)
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DOI：
10.1016/j.jnucmat.2011.01.036
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发表时间：
2011-04
影响因子：
3.1
通讯作者：
C. Pareige;S. Novy;S. Saillet;P. Pareige
中科院分区：
文献类型：
--
作者：
C. Pareige;S. Novy;S. Saillet;P. Pareige
已在原子尺度上研究了热老化 CF3M 双相不锈钢的铁素体。铸锭的加速时效已在实验室中在 350°C 下进行长达 200,000 小时（>20 年）。铁氧体微观结构的空间和化学演化已通过 3D 原子探针进行了表征。此外，还对相同样品进行了显微硬度测试。将所得结果与在 325°C（接近使用温度）时效的相同钢锭的铁素体以及现场时效的弯头钢的铁素体的显微组织和机械特性进行了比较。这项工作表明：(i) 350°C 的加速时效预示了 323°C 的现场时效，(ii) 显微硬度测量值与变化量 V（定义为时效样品的 Cr 频率分布与相同浓度的随机溶液的相应二项式分布特征之差的积分）之间的线性关系在 350°C 时效 200,000 小时后仍然有效，(iii) 活化能与旋节线分解和G相析出以及最后(iv)G相颗粒的粗化对铁素体显微硬度和V参数之间的关系没有影响。
The ferrite of thermally aged CF3M duplex stainless steels has been studied at the atomic scale. Accelerated ageing of ingots has been performed at 350°C in laboratory up to 200,000h (>20years). Spatial and chemical evolution of the microstructure of the ferrite has been characterised by 3D atom probe. In addition, micro-hardness has been performed on the same samples. The results obtained have been compared to the microstructural and mechanical characteristics of ferrite of the same ingots aged at 325°C (close to service temperature) and to the ferrite of an elbow steel aged on-site. This work has shown that: (i) accelerated ageing at 350°C anticipates the on-site ageing at 323°C, (ii) the linear relationship found between micro-hardness measurements and the variation V (defined as the integral of the difference between the Cr frequency distribution of the aged sample and the corresponding binomial distribution characteristic of a random solution with the same concentration) is still valid after 200,000h of ageing at 350°C, (iii) the activation energy is the same for both spinodal decomposition and G-phase precipitation and finally (iv) the coarsening of G-phase particles has no influence on the relationship between ferrite micro-hardness and the V parameter.