Mechanical properties and nanoparticles precipitation behavior of multi-component ultra high strength steel.
Mechanical properties and nanoparticles precipitation behavior of multi-component ultra high strength steel.
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多元超高强度钢的力学性能和纳米颗粒析出行为
DOI：
10.1016/j.matdes.2020.108637
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发表时间：
2020
影响因子：
8.4
通讯作者：
Caifu Yang
中科院分区：
文献类型：
--
作者：
Zhentuan Li;Feng Chai;Li Yang;Xiaobing Luo;Caifu Yang
研究了纳米Cu和Ni 3Al颗粒在多组元超高强度钢（UHSS）中的析出行为及其对力学性能的影响。采用HRTEM、XRD和EBSD等手段对超高强钢的析出相和基体组织进行了表征。Cu和Al的加入增加了马氏体的位错密度，促进了时效过程中Cu和Ni 3Al纳米粒子的共析出。Fe-Ni-Cu-Al钢在525 °C时效2 h时达到1350 MPa的屈服强度，其中约950 MPa是由位错强化和共沉淀强化贡献的。实验钢的位错密度在1015 m −2范围内，这导致了超过400 MPa的强化贡献。同时，极高的位错密度是纳米Cu和Ni 3Al颗粒共沉淀的优先析出位置。共沉淀强化的贡献为413 MPa，而Fe-Ni-Cu钢中仅依靠Cu沉淀强化的贡献仅为144 MPa。随着时效温度的升高，Ni 3Al颗粒的粗化速率比Cu颗粒的粗化速率快，导致Fe-Ni-Cu-Al钢的强化增量显著降低。
This study investigated the precipitation behavior of nanoscale Cu and Ni3Al particles in multi-component ultra-high strength steel (UHSS) and its influence on mechanical properties. The precipitation nanostructural features and matrix microstructural features of UHSS were carefully characterized by HRTEM, XRD and EBSD. Addition of Cu and Al in Fe-Ni steel increased the dislocation density of martensite and promoted the co-precipitation of Cu and Ni3Al nanoparticles upon aging. The Fe-Ni-Cu-Al steel achieved a yield strength of 1350 MPa at 525 °C aging for 2 h, of which ~950 MPa is contributed by dislocation strengthening and co-precipitation strengthening. The dislocation density in experimental steels was determined in the range of 1015m−2, which gave rise to a strengthening contribution of over 400 MPa. Meanwhile, the extremely high dislocation density acted as preferred precipitation sites for the co-precipitation of nanoscale Cu and Ni3Al particles. The contribution of co-precipitation strengthening was calculated as 413 MPa, while the contribution of strengthening relying on solely Cu precipitation in Fe-Ni-Cu steel was only 144 MPa. As increasing the aging temperature, Ni3Al particles showed faster coarsening rate than that of Cu particles, which led to a significant decrease in the strengthening increment of Fe-Ni-Cu-Al steel.