Advanced Structural Materials Group at PolyU Logo

Research Areas

(1) Advanced high-strength steels

Advanced ultrahigh-strength steels are of paramount importance in aerospace, automotive, nuclear power, maritime, and other high-tech industries. We are working on the development of next-generation ultra-high strength steels via co-precipitation of coherent nanoparticles.

 

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Selected publications:

1) Co-precipitation of nanoscale particles in steels with ultra-high strength for a new era, Materials Today 20(3), 142, 2017.

2) Hardening mechanisms and impact toughening of a high-strength steel containing low Ni and Cu additions, Acta Materialia 172,150, 2019.

3) Effects of welding and post-weld heat treatments on nanoscale precipitation and mechanical properties of a high strength steel, Acta Materialia 120, 216, 2016.

4) Precipitate transformation from NiAl-type to Ni2AlMn-type and its influence on the mechanical properties of high-strength steels, Acta Materialia 110, 31, 2016.

5) Precipitation mechanism and mechanical properties of an ultra-high strength steel hardened by nanoscale NiAl and Cu particles, Acta Materialia 97, 58, 2015.

6) Effects of Mn partitioning on nanoscale precipitation and mechanical properties of ferritic steels strengthened by NiAl particles, Acta Materialia 84, 283, 2015.

7) Synergistic effects of Cu and Ni on nanoscale precipitation and mechanical properties of high-strength steels, Acta Materialia 61, 5996, 2013.

 

 

(2) High-entropy alloys

Over the past decade, a new alloy design philosophy, i.e., high-entropy alloys which have equimolar or near-equimolar atomic fractions of multiple constituents, have drawn intensive interests. We are studying the nanoscale precipitation behavior of high-entropy alloys.

 

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Selected publications:

1) Multicomponent intermetallic nanoparticles and superb mechanical behaviors of complex alloys, Science 362, 933-937, 2018.

2) Superior high-temperature properties and deformation-induced planar faults in a novel L12-strengthened high-entropy alloy, Acta Materialia, 2020.

3) Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy, Acta Materialia 138, 72, 2017.

4) High-Entropy Alloy (HEA)-Coated Nanolattice Structures and Their Mechanical Properties, Advanced Engineering Materials 20, 1700625, 2018.

5) Microstructures and mechanical properties of CoCrFeMnNiVx high entropy alloy films, Journal of Alloys and Compounds 820, 153388, 2020.

 

 

(3) Stable nanocrystalline alloys (

(In collaboration with Prof. Christopher. A. Schuh at MIT)

Nanocrystalline materials are desirable in a wide variety of applications; however, nanocrystalline pure metals suffer from poor stability. We are examining the effect of solute species and segregation profiles on the stability of nanocrystalline alloys.

 

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Selected publications:

1) Nanocrystalline Ag-W alloys lose stability upon solute desegregation from grain boundaries, Acta Materialia 161, 194-206, 2018.

2) Attractive in situ self‐reconstructed hierarchical gradient structure of metallic glass for high efficiency, Advanced Functional Materials 1, 1807857, 2019.

3) High-Entropy Alloy (HEA)-Coated Nanolattice Structures and Their Mechanical Properties, Advanced Engineering Materials 20, 1700625, 2018.

 

 

(4) High-temperature titanium alloys

Titanium alloys are attractive materials for aerospace, military, and biomedical applications owning to their high specific strength. Our group is working on the design of advanced high-strength high-ductility titanium alloys by phase control and grain-boundary engineering..

 

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Selected publications:

1) Effects of boron on the fracture behavior and ductility of cast Ti-6Al-4V alloys, Scripta Materialia 100, 90, 2015.

2) Effects of boron and solutionizing treatments on microstructures and ductility of forged Ti-64 alloys, Journal of Alloys & Compounds 624, 170, 2015.

3) Improved ductility and oxidation resistance of cast Ti-6Al-4V alloys by microalloying, Journal of Alloys & Compounds 602, 235, 2014.

 

 

(5) Atom probe tomography of nanostructures

The Inter-University 3D Atom Probe Tomography Unit (APTU) was launched in June 2017 at CityU, which is equiped with the new-generation 3D atom probe tomography (LEAP 5000XR). We organized the 2017 Workshop on Applications of Atom Probe Tomography on December 4-5, 2017 at Hong Kong. We are interested in the APT characterization of multiphase and multicomponent alloys, such as ultrahigh-strength alloys, high-temperature alloys, lightweight alloys, nuclear materials, etc.

 

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Selected publications:

1) Nanocrystalline Ag-W alloys lose stability upon solute desegregation from grain boundaries, Acta Materialia 161, 194-206, 2018.

2) Effects of welding and post-weld heat treatments on nanoscale precipitation and mechanical properties of a high strength steel, Acta Materialia 120, 216, 2016.

3) Precipitate transformation from NiAl-type to Ni2AlMn-type and its influence on the mechanical properties of high-strength steels, Acta Materialia 110, 31, 2016.

4) Precipitation mechanism and mechanical properties of an ultra-high strength steel hardened by nanoscale NiAl and Cu particles, Acta Materialia 97, 58, 2015.

5) Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy, Acta Materialia 138, 72, 2017.

 

Research Equipment

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