The use of nanotechnology to improve the bulk and surface properties of steel for structural applications - Nanotechnology in Eco-efficient Construction - page 82

Production
process

Microstructure of bulk
material

Novel properties or
phenomenon Reference Steel type Mechanism(s)

Zhang et al.
(2011)

High-strength
α -steel (2.49%
Cu)

1000°C/1h +
quenching by
water +
500°C/200h

(FeAl) 2 B nanoparticles
along α GBs and
Cu-rich nano-
clusters in matrix

B-doping led to larger
elongation of the steel

B enhances the GB
cohesion and
inhibits the
integranular
fracture

Foroozmehr
et al. (2011)

Low-carbon
steels

Martensite
process:
quenching +
cold rolling +
annealing

Nano/sub-micron
scale α grains (e.g.,
142 nm)

Increasing the C content
or imposing larger
(rolling) reduction can
lead to fi ner ferrite
grains

C reduces the size of
blocks and packets
in lath α ′

Hosseini et al.
(2011)

Low-carbon steel
(0.13% C)

Martensite
process:
quenching +
plane strain
compression +
annealing

UTS of 1135 Mpa; El of
11.6%

Fragmentation of
the initial α ′ to α
grains

Xu et al. (2011) Ti-bearing

α ′ -steel

Tempering +
reheat
quenching

High density of
nano-precipitates
(1-10 nm) of TiC in
α ′ grains ( ∼ 8 μ m)

High yield strength
(1280 MPa) and impact
toughness (El of 13%
and impact energy of
32 J at − 40°C)

Strenghthening and
grain refi ning by
nano-TiC
precipitates and
toughening by
high % of high-
angle GBs