The use of nanotechnology to improve the bulk and surface properties of steel for structural applications - Nanotechnology in Eco-efficient Construction - page 86

Production
process

Microstructure of bulk
material

Novel properties or
phenomenon Reference Steel type Mechanism(s)

Li et al. (2011) Low-carbon steel

(0.12% C)

SPD: tempering + Nano-level

delaminated
microstructure with
α ′

Signifi cantly improved
high-cycle fatigue
properties

'Micro-cracks form
on the weak
interface of the
nano-grained steel
under low-stress
conditions' and
inhibit the
propagation of
main cracks

reheat
quenching +

cold rolling
(80% reduction)

lathes (average
100 nm thick)

Liu et al. (2010) 316 SS SPD: dynamic

plastic
deformation

∼ 20 vol% nanotwin

bundles embedded
in micro- and
nano-

UTS of 1 GPa; El of

23-27%

∼ Nanotwins with twin

boundaries that
act as slip planes
while resisting
dislocation
motion; low
dislocation density

Yan et al. (2012) 316 SS

+

annealing γ grains

Lu et al. (2012) 316 SS and

25Mn

Single-phase
hierachical
microstructure with
nanotwinned

Superior strength-
ductility synergy (e.g.,
yield strength of a few
GPa and very high
work-hardening rates)

γ -steel

grains: 'elastically
homogeneous but
plastically
heterogeneous'

γ

BOF: basic oxygen furnace; CSP: compact strip production; HE: hydrostatic extrusion.
RAFM: reduced activation ferritic/martensitic; UTS: ultimate tensile strength.