Origin of strong solid solution strengthening in the CrCoNi-W medium entropy alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2021年第14期
论文作者：Yujie Chen Yan Fang Xiaoqian Fu Yiping Lu Sijing Chen Hongbin Bei Qian Yu
摘 要：Solid solution strengthening is one of the most conventional strategies for optimizing alloys strength,while the corresponding mechanisms can be more complicated than we traditionally thought specifically as heterogeneity of microstructure is involved. In this work, by comparing the change of chemical distribution, dislocation behaviors and mechanical properties after doping equivalent amount of tungsten（W） atoms in CrCoNi alloy and pure Ni, respectively, it is found that the alloying element W in CrCoNi alloy resulted in much stronger strengthening effect due to the significant increase of heterogeneity in chemical distribution after doping trace amount of W. The large atomic scale concentration fluctuation of all elements in CrCoNi-3W causes dislocation motion via strong nanoscale segment detrapping and severe dislocation pile up which is not the case in Ni-3W. The results revealed the high sensitivity of elements distribution in multi-principle element alloys to composition and the significant consequent influence in tuning the mechanical properties, giving insight for complex alloy design.
Yujie Chen1，Yan Fang1，Xiaoqian Fu1，Yiping Lu2，Sijing Chen1，Hongbin Bei3，Qian Yu1
1. Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University2. Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology3. Institute for Superalloy Science and Technology, School of Materials Science and Engineering, Zhejiang University
摘 要：Solid solution strengthening is one of the most conventional strategies for optimizing alloys strength,while the corresponding mechanisms can be more complicated than we traditionally thought specifically as heterogeneity of microstructure is involved. In this work, by comparing the change of chemical distribution, dislocation behaviors and mechanical properties after doping equivalent amount of tungsten（W） atoms in CrCoNi alloy and pure Ni, respectively, it is found that the alloying element W in CrCoNi alloy resulted in much stronger strengthening effect due to the significant increase of heterogeneity in chemical distribution after doping trace amount of W. The large atomic scale concentration fluctuation of all elements in CrCoNi-3W causes dislocation motion via strong nanoscale segment detrapping and severe dislocation pile up which is not the case in Ni-3W. The results revealed the high sensitivity of elements distribution in multi-principle element alloys to composition and the significant consequent influence in tuning the mechanical properties, giving insight for complex alloy design.
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