Self-toughening crystalline Cu/amorphous Cu–Zr nanolaminates: Deformation-induced devitrification
Self-toughening crystalline Cu/amorphous Cu–Zr nanolaminates: Deformation-induced devitrification
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DOI：
10.1016/j.actamat.2013.11.061
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发表时间：
2014-03
期刊：
影响因子：
9.4
通讯作者：
J. Y. Zhang;Gang Liu;Sun Jinru
中科院分区：
文献类型：
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作者：
J. Y. Zhang;Gang Liu;Sun Jinru
如何克服强度与韧性的冲突，并在金属晶体或金属玻璃家族中达到前所未有的损伤容限，是结构材料设计的一个巨大挑战。当组成层接近关键的内部特征尺寸时，玻璃纳米层和晶态纳米层的组合可以表现出极高的韧性，即优异的强度和高的延展性。采用三点弯曲和单轴微压试验研究了等厚度∼50 nm铜/铜-锆晶态/非晶态纳米层化物(C/ANL)的增韧行为。被非晶相吸收的位错不仅形成了无缺陷的纳米晶，而且在玻璃纳米层中形成了纳米晶。结果表明，由于晶态/非晶态界面对裂纹扩展的外在屏蔽作用，以及与玻璃纳米层脆韧转变相关的本征形变诱导脱玻璃化机制，Cu/CuZZC/ANLS具有自增韧作用。研究结果表明，玻璃材料潜在的高损伤容忍度可以超出基准范围，达到以前金属晶体-非晶态复合材料无法达到的水平。
How to defeat the conflict of strength vs. toughness and achieve unprecedented levels of damage tolerance within either metallic crystalline or metallic glassy family is a great challenge for designing structural materials. The combination of glassy with crystalline nanolayers can manifest extraordinarily high toughness, i.e. superior strength in conjunction with high ductility, when the constituent layers approach a critical internal feature size. Three-point bending and uniaxial microcompression tests were performed on Cu/Cu–Zr crystalline/amorphous nanolaminates (C/ANLs) with equal layer thicknesses ∼50 nm to investigate their toughening behaviors. The dislocations absorbed by the amorphous phase not only render defect-free nanocrystals, but also create nanocrystallites in glassy nanolayers. It is revealed that the Cu/Cu–Zr C/ANLs self-toughen via the combination of the extrinsic shielding effect of crystalline/amorphous interfaces on a crack growth accommodated by an extensive shear-band sliding process and the intrinsic deformation-induced devitrification mechanism associated with the brittle-to-ductile transition of glassy nanolayers. The findings indicate that the high damage tolerance potentially accessible to glassy materials can extend beyond the benchmark ranges towards levels previously inaccessible to metallic crystalline–amorphous composites.