材料科学
无定形固体
纳米压痕
复合材料
纳米复合材料
透射电子显微镜
剪切带
微观结构
应变硬化指数
复合数
非晶态金属
变形(气象学)
纳米技术
可塑性
结晶学
合金
化学
作者
Basudeb Sahu,Wenqian Wu,Jian Wang,Amit Misra
出处
期刊:Physical Review Materials
[American Physical Society]
日期:2022-09-07
卷期号:6 (9)
被引量:4
标识
DOI:10.1103/physrevmaterials.6.094002
摘要
Deformation mechanisms in sputter-deposited crystalline Al/amorphous Si nanocomposites with nanolaminate or nanofibrous morphology are characterized by nanoindentation, micropillar compression testing and transmission electron microscopy (TEM). The nanofibrous composite having crystalline Al nanofibers with \ensuremath{\sim}40--50 nm in length and 15--20 nm in diameter embedded in amorphous Si exhibits strain hardening to a maximum flow stress of 2.9 GPa and no shear band (SB) formation in compression up to plastic strain exceeding 24%. On the other hand, nanolaminate composite that is composed of 80 nm crystalline Al layers and 20 nm amorphous Si layers exhibits catastrophic SBs starting at plastic strains in the range of 5--10%. Cross-sectional TEM of the deformed samples reveals a high density of stacking faults and twin boundaries in Al nanofibers and no microshear bands in the nanofibrous composite, suggesting plastic deformation in amorphous Si phase and crystalline Al nanofibers. Molecular dynamics simulations revealed that the plastic deformation in amorphous Si phase in the cosputtered films could be favored by the decrease in flow strength of amorphous Si with increasing Al solute concentration trapped in Si.
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