Kefu Yao

Prof. Kefu Yao


Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 March 2006 in Applied Physics Letters
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Journal Article
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KYKefu Yao
Kefu Yao
FRF. Ruan
F. Ruan
YYY. Q. Yang
Y. Q. Yang
NCN. Chen
N. Chen
Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<2%) at room temperature. We report a newly developed Pd–Si binary bulk metallic glass, which exhibits a uniform plastic deformation and a large plastic engineering strain of 82% and a plastic true strain of 170%, together with initial strain hardening, slight strain softening and final strain hardening characteristics. The uniform shear deformation and the ultrahigh plasticity are mainly attributed to strain hardening, which results from the nanoscale inhomogeneity due to liquid phase separation. The formed nanoscale inhomogeneity will hinder, deflect, and bifurcate the propagation of shear bands.

21 April 2022 in Nature Communications
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HLHengwei Luan
Hengwei Luan
XZXin Zhang
Xin Zhang
HDHongyu Ding
Hongyu Ding
FZFei Zhang
Fei Zhang
JLJ. H. Luan
J. H. Luan
KYKefu Yao
Kefu Yao
Glass-to-glass transitions are useful for us to understand the glass nature, but it remains difficult to tune the metallic glass into significantly different glass states. Here, we have demonstrated that the high-entropy can enhance the degree of disorder in an equiatomic high-entropy metallic glass NbNiZrTiCo and elevate it to a high-energy glass state. An unusual glass-to-glass phase transition is discovered during heating with an enormous heat release even larger than that of the following crystallization at higher temperatures. Dramatic atomic rearrangement with a short- and medium-range ordering is revealed by in-situ synchrotron X-ray diffraction analyses. This glass-to-glass transition leads to a significant improvement in the modulus, hardness, and thermal stability, all of which could promote their applications. Based on the proposed high-entropy effect, two high-entropy metallic glasses are developed and they show similar glass-to-glass transitions. These findings uncover a high-entropy effect in metallic glasses and create a pathway for tuning the glass states and properties.

27 March 2015 in RSC Advances
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YTY. Tang
Y. Tang
YSY. Shao
Y. Shao
NCN. Chen
N. Chen
XLXue Liu
Xue Liu
SCS. Q. Chen
S. Q. Chen
KYKefu Yao
Kefu Yao
Improving intrinsic reactivity is one of the key requirements in applying zero-valent iron in the field. As a new kind of zero-valent iron, iron based amorphous alloys were recently found to be capable of rapidly remediating wastewater. However, the mechanisms for the rapid degradation have not yet been fully understood. In this study, commercial Fe–Si–B amorphous alloy ribbons (Fe–Si–BAR) were used to degrade azo dyes (Direct Blue 6 and Orange II) to study the reaction kinetics, pathway and mechanism behind the high reactivity of these iron based amorphous alloys. The results show that, under the same conditions, the surface normalized reaction rate constants for the decomposition of Orange II and Direct Blue 6 by Fe–Si–BAR could be 1300 and 60 times larger respectively than those obtained by using 300 mesh iron powders. Through UV-vis spectrophotometry and mass spectrometry, it is found that the intermediate products of the azo dyes degraded by Fe–Si–BAR are similar to those produced in degradation by iron powders. However, the controlling step of the degradation reaction by Fe–Si–BAR turns out to be the diffusion process rather than the surface chemical reaction found in the reaction by iron powders. Further analysis indicates that the high degradation efficiency of Fe–Si–BAR results from its amorphous structure and the metalloid additions, which could enhance the catalytic effect and promote the formation of a non-compact and easily detached oxide layer on the surface. The experiments under different environmental conditions show that the factors that influence the degradation efficiency of crystalline iron powders affect that of Fe–Si–BAR in a similar way, but Fe–Si–BAR is capable of efficiently degrading wastewater under broader conditions than the crystalline iron powders. The results indicate that Fe–Si–BAR is a promising environmental catalyst for wastewater treatment.

5 December 2014 in RSC Advances
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YTYao Tang
Yao Tang
YSYang Shao
Yang Shao
NCNa Chen
Na Chen
KYKefu Yao
Kefu Yao
The morphology and the degradation ability of three different materials (200 mg L −1 DB6, 25 °C, initial pH = 7).

4 November 2016 in Metals
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Pan GongPan Gong
Pan Gong
LDLei Deng
Lei Deng
JJJunsong Jin
Junsong Jin
SWSibo Wang
Sibo Wang
XWXy Wang
Xy Wang
KYKefu Yao
Kefu Yao
Ti-based bulk metallic glasses (BMGs) are very attractive for applications because of their excellent properties such as high specific strength and high corrosion resistance. In this paper, we briefly review the current status of the research and development of Ti-based bulk metallic glasses. Emphasis is laid on glass-forming ability, mechanical properties, corrosion resistance, and biocompatibility.

25 July 2014 in Scientific Reports
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XLXue Liu
Xue Liu
YSYang Shao
Yang Shao
YTYao Tang
Yao Tang
KYKefu Yao
Kefu Yao
Preparation of surface enhanced Raman scattering (SERS) nanostructures with both high sensitivity as well as high reproducibility has always been difficult and costly for routine SERS detection. Here we demonstrate air-stable metallic glassy nanowire arrays (MGNWAs), which were prepared by a cheap and rapid die nanoimprinting technique, could exhibit high SERS enhancement factor (EF) as well as excellent reproducibility. It shows that Pd40.5Ni40.5P19 MGNWA with nanowires of 55 nm in diameter and 100 nm in pitch possesses high SERS activity with an EF of 1.1 × 105, which is 1–3 orders of magnitudes higher than that of the reported crystal Ni-based nanostructures, and an excellent reproducibility with a relative standard deviation of 9.60% measured by 121 points over an area of 100 μm*100 μm. This method offers an easy, rapid, and low-cost way to prepare highly sensitive and reproducible SERS substrates and makes the SERS more practicable.