Research

Some current research topics:

(1)  Deformation mechanism and delayed fracture of TWIP steels

 

(a) Massive twins formed in a TWIP steel after large deformation; (b) atomic structure a single deformation twin.

APT


(2) Twinning and martensitic transformation in micro-pillars


(a) Stress-strain curves of the pillars under compression; (b) SEM image of Pillar 1 after compression showing formation of twins

(3) High-modulus low-density steel composite


(a) SEM image of the steel composite;  (b) EBSD orientation map of ferrite.

(a) Nanoindentation curves on different TiB2 particles. (b) The corresponding SEM images. The dashed rectangle in I2 shows the location where the TEM sample was made by FIB. (c) TEM image of the cross-section of I2, showing high dislocaitond density at the interface. Interfacial yielding takes place before de-bonding, indicating an excellent intefacial property.


(4) Medium Mn-TRIP steel

(a) EBSD map of a 5Mn TRIP steel (red: ferrite, yellow: austenite); (b) nanoindenation curves of austenite and ferrite; (c) nano-hardness distribution of austenite grains and ferrite grains.
(5) High strain rate deformation of steels

qp-hs

True stress-strain curves of QP1500 under high strain rate and quasi-static loading. T-EBSD of showing austenite (color) and martesntie (grey).