Engineering topics

Lu, Yiping

Publications and source records attributed to Lu, Yiping.

3 records

DOE OSTI2018

Effects of Tungsten Addition on the Microstructure and Mechanical Properties of Near-Eutectic AlCoCrFeNi{sub 2} High-Entropy Alloy

The effects of tungsten addition on the microstructure and mechanical properties of near-eutectic AlCoCrFeNi{sub 2} high-entropy alloy were investigated in this paper. The AlCoCrFeNi{sub 2}W{sub x} alloys comprised the primary BCC phase plus eutectic FCC/BCC phases. It was found that W element can both promote the formation of the primary BCC phase and act as a solid solution strengthening element. The hardness of the AlCoCrFeNi{sub 2}W{sub x} alloys increased from HV 293 to HV 356.2 with the increase in W content. The addition of W element improved the strength of alloys but reduced ductility. Thereinto, the AlCoCrFeNi{sub 2}W{sub 0.2} alloy showed the most excellent compressive properties with the fracture strength of 2785.9 MPa and the plastic strain of 0.42, respectively, which implied the potential industrial application values.

36 MATERIALS SCIENCE↗

DOE OSTI2018

A new strategy to design eutectic high-entropy alloys using simple mixture method

Eutectic high entropy alloys (EHEAs) hold promising industrial application potential, but how to design EHEA compositions remains challenging. In the present work, a simple and effective strategy by combining mixing enthalpy and constituent binary eutectic compositions was proposed to design EHEA compositions. This strategy was then applied to a series of (CoCrFeNi)M x (M = Nb, Ta, Zr, Hf) HEAs, leading to the discovery of new EHEAs, namely, CoCrFeNiNb 0.45 , CoCrFeNiTa 0.4 , CoCrFeNiZr 0.55 and CoCrFeNiHf 0.4 . The microstructure of these new EHEAs comprised of FCC and Laves phases in the as-cast state. In conclusion, the experimental result shows that this new alloy design strategy can be used to locate new EHEAs effectively.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Enhancing multi-step quantum state tomography by PhaseLift

Multi-photon system has been studied by many groups, however the biggest challenge faced is the number of copies of an unknown state are limited and far from detecting quantum entanglement. The difficulty to prepare copies of the state is even more serious for the quantum state tomography. One possible way to solve this problem is to use adaptive quantum state tomography, which means to get a preliminary density matrix in the first step and revise it in the second step. In order to improve the performance of adaptive quantum state tomography, we develop a new distribution scheme of samples and extend it to three steps, that is to correct it once again based on the density matrix obtained in the traditional adaptive quantum state tomography. Our numerical results show that the mean square error of the reconstructed density matrix by our new method is improved to the level from 10{sup −4} to 10{sup −9} for several tested states. In addition, PhaseLift is also applied to reduce the required storage space of measurement operator. - Highlights: • PhaseLift is firstly applied in the adaptive quantum state tomography and the required store space of measurement operator is reduced. • Traditional adaptive quantum state tomography is extended to three-step adaptive quantum state tomography. • A new scheme of copy distribution of state is proposed to effectively use the limited copies of state. • For several tested states, the mean square error of the reconstructed state is reduced to 10{sup −9} from 10{sup −4}. • Fidelity is more accurately estimated with limited copies of state compared with traditional adaptive quantum state tomography.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗