Transformation-induced plasticity in bulk metallic glass composites evidenced by in-situ neutron diffraction
Transformation-induced plasticity in bulk metallic glass composites evidenced by in-situ neutron diffraction
复制标题
原位中子衍射证明了块体金属玻璃复合材料中相变诱导的塑性
DOI：
10.1016/j.actamat.2016.11.029
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发表时间：
2017-02-01
期刊：
影响因子：
9.4
通讯作者：
Lu, Z. P.
中科院分区：
文献类型：
--
作者：
Wu, Y.;Ma, D.;Lu, Z. P.
通过原位中子衍射结合分子动力学模拟研究了由奥氏体 B2 相组成的应变软化非晶基体中的相变诱导塑性。研究发现，加载时从B2到B19'的马氏体转变始于宏观屈服，随着母体奥氏体B2相比例的减少而增加，并且不同样品中马氏体转变的阈值晶格应变几乎相同，表明当前玻璃基体中的马氏体转变是应变控制的。载荷分配和应变调节分析表明B2具有弹性各向异性，B2与非晶基体良好的弹性匹配保证了良好的协同变形。此外，分子动力学模拟表明，B2与非晶基体界面处的原子偏离了标准B2晶格，并充当马氏体转变的成核位点，最终引起应变控制的马氏体转变。我们的研究结果为微观层面上相变介导的塑性机制提供了新的见解，并对开发新型高性能块状金属玻璃复合材料具有有益的启示。(c) 2016 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
Transformation-induced plasticity in a strain-softening amorphous matrix consisting of austenite B2 phase was studied by in-situ neutron diffraction, coupled with molecular dynamic simulation. It was found that the martensitic transformation from B2 to B19' upon loading commenced at the macroscopic yielding which increased with the decrease of the fraction of the parent austenite B2 phase, and the threshold lattice strain for the martensitic transformation is almost the same in different samples, suggesting that the martensitic transformation in the current glassy matrix is strain-controlled. Analysis of load partition and strain accommodation unveiled that B2 has elastic anisotropy, and the desirable elastic match between B2 and the amorphous matrix ensures a good cooperative deformation. Additionally, molecular dynamic simulation revealed that atoms at the interface between B2 and the amorphous matrix deviated from the standard B2 lattices and acted as nucleation site for the martensitic transformation, eventually giving rise to the strain-controlled martensitic transformation. Our findings provide new insights into the mechanism of phase transformation-mediated plasticity at the microscopic level, and have useful implications for developing novel, high-performance bulk metallic glass composites.(c) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.