Researchers

Associate Professor Ting-Guang LIU

Keywords：Grain boundary engineering; Stress corrosion cracking; 3D materials science; Nuclear materials

Contact：tgliu@ustb.edu.cn

Researches

(1) Grain boundary engineering (GBE): The lattice structure of grain boundaries in a polycrystalline material determine many of its physical and chemical properties, such as its yield strength, creep, and resistance to intergranular degradation. The grain boundary character distribution of a material can be optimized, i.e. including more CSL boundaries, so that the material will perform higher resistance to intergranular degradation.

(2) Stress corrosion cracking (SCC): SCC is a dominating mechanical property in the reliability of most structural materials, especially in corrosive environment. The interaction of materials, environments and stress controls a SCC process. GBE was studied to restrain intergranular SCC.

(3) 3D materials science (3DMS): Materials science became a discipline with the advent of metallography, which built a bridge – microstructure – properties and processing. 2D metallography has been very successful, but some phenomena must be understood in 3D.

(4) Nuclear materials: All of my researches on GBE, SCC and 3DMS focus on structural materials serving in nuclear reactors or thermal power plants, such as austenitic stainless steels, Ni-based alloys, copper alloys.

l  Main Projects

- Project 1：” National Natural Science Foundation of China”, “Study of effects of grain boundary network characteristics on intergranular stress corrosion cracking of austenitic stainless steel by using three-dimensional characterization”, total fund 260000 RMB, 2018-2020

- Project 2：” Beijing Natural Science Foundation”, “study on intergranular degradation and grain boundary enhancement of austenitic stainless steel in supercritical water”, total fund 200000 RMB, 2018-2020

- Project 3：” Fundamental Research Funds for the Central Universities”, “Effects of grain boundary network characters on stress corrosion cracking of austenitic stainless steel in supercritical water”, total fund 100000 RMB, 2017-2018

l  Main Contributions

- Development of thermo-mechanical process for grain boundary engineering (GBE). Investigation of grain boundary network evolution and multiple-twinning process during GBE.

- The Microstructures of GBE processed and conventional materials were investigated and compared by EBSD and 3D-EBSD. 3D grains and grain boundaries were visualized and analyzed quantitatively, in particular, the 3D twins and twin boundaries.

- The grain boundary networks of GBE processed and conventional materials were investigated in morphological and topological in 3D. Arrangement of twin boundaries in triple-junction, quadruple-junction and twin-related domain were studied.

- Cracking susceptibility of CSL and random boundaries during intergranular SCC of GBE processed 316 stainless steel in simulated PWR water.

- 3D characterization of intergranular SCC paths by 3D-OM coupled with 3D-EBSD. Investigation of topological modes of intergranular SCC propagating through quadruple junctions, finding that the propagation of intergranular SCC can be hindered by triple junctions or quadruple junctions in the presence of twin boundaries.

l  Publications

1.     Tingguang Liu, Shuang Xia, Donghai Du, Qin Bai, Lefu Zhang, Yonghao Lu. Grain boundary engineering of large-size 316 stainless steel via warm-rolling for improving resistance to intergranular attack. Materials Letters, 2019, 234: 201-204.

2.     Tingguang Liu, Shuang Xia, Bangxin Zhou, Qin Bai, Gregory S. Rohrer. Three-dimensional study of twin boundaries in conventional and grain boundary engineered 316L stainless steels. Journal of Materials Research, 2018, 33(12): 1742-1754.

3.     Tingguang Liu, Shuang Xia, Bangxin Zhou, Qin Bai, Gregory S. Rohrer. Three-dimensional geometrical and topological characteristics of grains in conventional and grain boundary engineered 316L stainless steel. Micron, 2018, 109: 58-70.

4.     Tingguang Liu, Shuang Xia, Qin Bai, Bangxin Zhou, Lefu Zhang, Yonghao Lu, Tetsuo Shoji. Three-dimensional study of grain boundary engineering effects on intergranular stress corrosion cracking of 316 stainless steel in high temperature water. Journal of Nuclear Materials, 2018, 498: 290-299.

5.     Tingguang Liu, Shuang Xia, Tetsuo Shoji, Qin Bai, Bangxin Zhou, Yonghao Lu. The topology of three-dimensional grain boundary network and its influence on stress corrosion crack propagation characteristics in austenitic stainless steel in a simulated BWR environment. Corrosion Science, 2017, 129: 161-168.

6.     Tingguang Liu, Shuang Xia, Bangxin Zhou, Qin Bai, Gregory S. Rohrer. Three-dimensional characteristics of the grain boundary networks of conventional and grain boundary engineered 316L stainless steel. Materials Characterization, 2017, 133: 60-69.

7.     Tingguang Liu, Shuang Xia, Baoshun Wang, Qin Bai, Bangxin Zhou, Cheng Su. Grain orientation statistics of grain-clusters and the propensity of multiple-twinning during grain boundary engineering. Materials Design, 2016, 112: 442-448.

8.     Tingguang Liu, Shuang Xia, Hui Li, Bangxin Zhou, Qin Bai. The highly twinned grain boundary network formation during grain boundary engineering. Materials Letters, 2014, 133: 97-100.

9.     Tingguang Liu, Shuang Xia, Hui Li, Bangxin Zhou, Qin Bai. Effect of the pre-existing carbides on the grain boundary network during grain boundary engineering in a nickel based alloy. Materials Characterization, 2014, 91: 89-100.

10.  Tingguang Liu, Shuang Xia, Hui Li, Bangxin Zhou, Qin Bai, Cheng Su, Zhigang Cai. Effect of initial grain sizes on the grain boundary network during grain boundary engineering in Alloy 690. Journal of Materials Research, 2013, 28(9): 1165-1176.

l  Awards and Membership

PhD student national scholarship

President scholarship of Shanghai University

Frontrunner 5000

Excellent academic paper award of China Nuclear Society