Prof. Yonghai Yue[Beihang University]

Title: In situ study of the strengthening and toughening mechanisms of nano-based composites

Time: 9:00 - 10:00 AM, Thursday, May 20, 2021

Place: Conference room A417, HPSTAR (Beijing)

Tencent meeting: https://meeting.tencent.com/s/L2SPTmX51jBs , Meeting ID: 752 655 929

Host: Xiang Gao

Abstract:

In this talk, Prof. Yue will introduce his recent work about the super hard and tough diamond.

The well known trade off between hardness and toughness makes simultaneous improvement of

both properties challenging, especially in diamond. Here they report the structural characterization

of adiamond composite hierarchically assembled with coherently interfaced diamond polytypes,

interwoven nanotwins and interlocked nanograins. The architecture of the composite enhances

toughness more than nanotwinning alone, without sacrificing hardness.Singleedge notched beam

tests yield a toughness up to five times that of synthetic diamond,even greater than that of magnesium

alloys. When fracture occurs, a crack propagates through diamond nanotwins of the 3C (cubic) polytype

along {111} planes, via a zigzag path. As the crack encounters regions of non 3C polytypes, its propagation

is diffused into sinuous fractures,with local transformation into 3C diamond near the fracture surfaces.

Both processes dissipate strain energy,thereby enhancing toughness.This work could prove useful in

making superhard materials and engineering ceramics.

Biography of the Speaker:

Professor Yonghai Yue

College of Chemistry, Beihang University, Beijing China
Email: yueyonghai@buaa.edu.cn

· Education

2006.9-2012.7 Beijing University of Technology, Ph.D.

· Working Experience

2012.12-2016.7 Beihang University, Lecturer

2014.9-2015.9 Arizona State University, Visiting scholar

2016.7-2020.3 Beihang University Ass.Prof.

2020-present Beihang University, Professor

· Research Interests

1. In-situ study ofstrengthening and toughening mechanism of structural materials;

2. Design and performancecharacterization of new lightweight and high-strength composites.

· Selected Publications

1. Yonghai Yue et al., Nature, 2020, 582, 370;

2. Yonghai Yue* and Lin Guo*, ACS Nano, 2019, 13, 4191;

3. Yonghai Yue* and Lin Guo*, Adv. Funct. Mater, 2018, 28, 1801614

4. YonghaiYue*, Lin Guo* and Xun Wang*, JACS, 2017, 139, 8579;

5. Yonghai Yue et al., Nature Communications, 2016, 7,12251.