EXPLOSIVE PRODUCTION OF ULTRAFINE-GRAINED MATERIALS ...

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29 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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EXPLOSIVE PRODUCTION OF ULTRAFINE
-
GRAINED MATERIALS



Yu. A. Gordopolov
a
, S. S. Batsanov
a
, V. A. Veretennikov
a
,

N. G. Zaripov
b
, and L. V. Gordopolova
a


a
Institute of Structural Macrokinetics and Materials Science, Chernogolovka,
Moscow, 142432 Russia

b
State Aviation Technical University, Ufa, 450000 Russia

e
-
mail: gordop@ism.ac.ru




Contents


Shock compression of nanopowders




Dynamic
-
isostatic pressing of ultrafine powders



Shock
-
induced refining of grains in materials



Shock quenching of SHS products


Conclusion




SHOCK COMPRESSION OF NANOPOWDERS

Pressing with cylindical geometry


ampoule

(
ductile metal
)


ED

HE

starting
powder

plug


Decaying mode
(
underpressing
)

Regular mode

(
homogeneity
)

Mach mode
(
overpressing
)

P

=

0
DU

D

=
c
0
+
bU

P
I
~
D
2
;
P
II
~
D
2


P
I
>
P
II

I

D


D


II

starting powder
(Ni)



mean particle size
56
nm

Resultant monolith material (Ni)

after shock compaction and thermal
treatment (6OO

C,
15
min)

mean


particle size < 100 nm

hardness
47

HRC

bending strength
1100
MPa



TEM
photograph
of final Ni
sample

ED

KBr

HE

foil


starting powders (diamond
/
w
-
BN
)


ampoule

(
steel
)

DYNAMIC
-
ISOSTATIC PRESSING OF ULTRAFINE
POWDERS


particle size
(
polycryst.
)


3
-
10

m



獩z攠o映獩ngl攠捲y獴慬猠in p慲瑩捬e猠 㰠
㄰〠



晩n慬 捯浰慣琠
(
di慭and
/
w
-

)


grain size in central area


10
nm

hardness

8


3

HV


grain size at periphery



30
nm

hardness



(
2
-
3
)


3
HV


compression strength (until cracking)

10
t
/
cm
2







SHOCK
-
INDUCED REFINING OF GRAINS

IN METALS

(dynamic recrystalization)

Microstructure of Al

4% Cu

0.5% Zr mixture

at different depth from the surface of loading

5 mm

7 mm



F

REFINEMENT OF CERMET GRAINS

DURING HOT DEFORMATION


Experimental setup







rapid deformation
(dynamic loading)



D

final shape
of samples

initial sample
(TiC
0,47

SHS
compact at 950
0
C)

slow deformation
(quasi
-
static loading)


= 10

4

10

3
s

1



=

0
.
7

0
.
8


~

10
6

s
-
1



~

0
.
1

punch

force (10 ton)

ED

lens

HE

metal matrix


shock wave (10
3
m/s)



MICROSTRUCTURE OF TITANIUM CARBIDE SUBJECTED
TO RAPID HOT DEFORMATION

(SHOCK COMPRESSION)

(
a
)

(
b
)

(
c
)

(
d
)

Microstructure of (a) starting TiC
0
.
47

and (b

d) its evolution during rapid (dynamic)

hot deformation (high

).




MICROSTRUCTURE OF TITANIUM CARBIDE
SUBJECTED TO SLOW HOT DEFORMATION
(SUPERPLASTIC MODE)

Microstructure of TiC
0
.
6

obtained by superplastic (quasi
-
static) deformation of

TiC
0
.
47

(low )





CHEMICAL COMPOSITION OF TITANIUM
CARBIDE GRAINS DURING HOT
DEFORMATION

Lattice parameter of TiC
x

vs. strain


for dynamic (

) and quasi
-
isostatic (

) loading

Lattice parameter, Å


4.325


4.300


4.305


4.310


4.315


4
.320


0 0.25 0.50

0.75 1.00

Strain

, rel. units


TiC
0.75

TiC
0.47

TiC
0.55

TiC
0.58

TiC
0.6

4.295

4.290

FINE STRUCTURE OF TITANIUM CARBIDE
DURING RAPID HOT DEFORMATION

(
a
)

(
b
)

(
c
)

Changes in the fine structure of TiC
x

during hot deformation: (a) development of
intergranular sliding, formation of dislocation walls and subgrains, (b) precipitation
of tabular Ti, and (c) formation of fine
-
grained microduplex structure.

SHOCK QUENCHING of SHS PRODUCTS

Highly dense materials with

controlled grain size

Detonation delay
,
s

80

90

100

0

120

240

360


Relative density
, %

C/Ti = 0.47

C/Ti = 0.76

C/Ti = 1.00

C/Ti = 1.00

ED

HE

Green
mixture

Flying plate


Plug

Container

Igniter


TC

0.8

0.6

1.0

1.2

0

120

240

360


Mean grain size
,

m

C/Ti = 0.47

C/Ti = 0.76

C/Ti = 1.00

C/Ti = 1.00

Detonation delay
,
s

0 50 100

GRADED AND LAYERED MATERIALS BY
SHOCK QUENCHING OF SHS PRODUCTS




product

reaction zone

green mixture

Combustion wave

TiSi

Ti + Si

Ti + Si

Ti + C

Cu

R
/
R
max

Ti ( ), C ( ), Si ( ), Cu ( )

1.0

0.8

0.6

0.4

0.2

d
,

m


L
,

m

10

8

6

4

2

Combustion wave

TiC

Cu

TiSi

CONCLUSION


Action

of

shock

waves

on

materials

is

an

effective

tool

for

modification

of

their

structure

and

hence

properties
.


Different

options

for

application

of

shock

waves

afford

preparation

of

different

materials

with

unique

properties,

including

ultrafine
-
grained

and

nano
-
structured

ones,

for

various

practical

implementations
.