Deformation behavior of metallic glass composites and plasticity accommodation at microstructural length-scales
Deformation behavior of metallic glass composites and plasticity accommodation at microstructural length-scales
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DOI：
10.1016/j.mtcomm.2020.101237
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发表时间：
2020-09-01
影响因子：
3.8
通讯作者：
Mukherjee, Sundeep
中科院分区：
文献类型：
--
作者：
Hasannaeimi, Vahid;Muskeri, Saideep;Mukherjee, Sundeep
块体金属玻璃基复合材料代表了一种独特的微观结构设计策略，克服了结构合金的强度/延展性权衡。研究了钛基大块非晶复合材料在微观尺度上的力学行为。非晶基体上的微柱表现出1.9 GPa的平均屈服点，随后是剪切带的锯齿状塑性变形特征。相比之下，结晶枝晶相上的微柱显示出低得多的屈服强度，平均为0.72 GPa，对于所选择的四种不同的结晶取向，平滑的塑性流动，没有可识别的载荷突发，以及屈服点后的稳定的应变硬化。在玻璃态基体和枝晶的界面处形成了大量的微柱。混合微柱的变形均匀，塑性大，这是由于其储存的弹性能较小。在非晶基体中开始的剪切带被晶体枝晶阻止，晶体枝晶通过滑移带和位错堆积来容纳塑性。塑性变形后，界面保持完整，在非晶相中没有可观察到的失透迹象。
Bulk metallic glass matrix composites represent a unique microstructural design strategy for overcoming the strength/ductility trade-off in structural alloys. Site-specific mechanical behavior of a Ti-based bulk metallic glass composite was evaluated at microstructural length-scale. The micro-pillars on the amorphous matrix showed an average yield point of 1.9 GPa followed by serrated plastic deformation characteristic of shear banding. In contrast, micro-pillars on the crystalline dendritic phase showed a much lower yield strength of 0.72 GPa on average for the four different crystallographic orientations chosen, smooth plastic flow with no recognizable load burst, and stable strain-hardening after yield point. A number of micro-pillars were made at the interface between the glassy matrix and the crystalline dendrite. The mixed micro-pillars showed homogeneous deformation and greater plasticity which was attributed to their smaller stored elastic energy. Shear bands initiated in the amorphous matrix were arrested by the crystalline dendrite, which accommodated plasticity through slip bands and dislocations pile-ups. The interface remained intact after plastic deformation, with no observable signs of devitrification in the amorphous phase.