(SANITIZED)UNCLASSIFIED SOVIET PAPER ON CRYSTAL PROPERTIES AND GRAIN SUBSTRUCTURE ON HARDNESS(SANITIZED)

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80T00246A016300130001-6
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 10
• Document Creation Date: December 22, 2016
• Document Release Date: January 6, 2012
• Sequence Number: 1
• Publication Date: May 2, 1962
• Content Type: REPORT

Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
Next 2 Page(s) In Document Denied
Iq
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
THE INFLUENCE OF CRYSTAL PROPERTIES AND GRAIN SUBSTRUCTURE ON HARDNESS
1. Fe-Ni AND Fe-Si ALLOYS*
V.M. KARDONSKII, V.G. KURDYUMOV and M.D. PERKAS
Institute of Metallography and Metal Physics,
Central Research Institute of Ferrous Metallurgy
(Received 26 August 1960)
An investigation has been made of the temperature dependence of yield point and hardness in
alloys in the annealed and strain-hardened states. Analysis of the experimental data confirms pre-
vious conclusions that the resistance of a strain-hardened material to deformation is determined by
two factors: the crystal properties of the material (resistance to the movement of dislocations in-
side the regions of a crystal which are free of subboundaries) and granular substructure (the size
of submicroregions, presence of internal boundaries in the grain, degree of disorientation of the
separate regions). On the basis of the additivity of the effect of both"
oth vectors calculation has been
made of the temperature dependence of the hardness of a strain-hardened alloy and it has been
compared with experimental data. A relationship has been established between the magnitude of
type II distortions and temperature dependence of as and HY.
In investigations of binary alloys of iron it has
been
The established that after the same degree of cold ter ticsirect connexion between the strength charac-
(80 0) strength will be renter in an (hardness, yield point) of strain-hardened
g alloys and the extent of second-type distortions
alloy which has undergone a high degree of second-
grade distortion (microstt?esses). After strengthenin can be attributed not the presence of these consi-
the size of the regions of coherent scattering (blocks) of these alloysthave non-unhiformcprope tlies, events
was practically the same for all the alloys, being the annealed ..._._ ,
.100-,400 c- ., n in
11
already in the investigation of the fine structure and
mechanical properties of quenched steels with differ-
ent carbon contents [2, 3].
From an analysis of the experimental material
the suggestion can be put forward [1, 3, 41, that the
actual second-type distortions which arise on
strengthening are not a major factor in increasing the
resistance of a material to plastic deformation. The
accuracy of this proposition was then confirmed ex-
perimentally in papers [5-7, 9]. The conclusion was
drawn that the most important crystallostructural
factors responsible for the strengthening of metals
and alloys is the break-up of the grain into fragments
10" and 10-? cm in size with considerable disorien-
tation among the {raiment, ;:nd the formation of
internal submicroscopic regions of coherent scatter-
ing of X-rays [1, 3, 71.
* Fiz. metal. metallorrd., 609-614, 1961.
-6 properties which determine the resist
t
e
ance of
non
strain-hardened materials to the passage of ele-
mentary acts of plastic deformation (resistance to
the movement of dislocations in the sector free of
sub-boundaries). The extent of the second-type
distortions in a strain-hardened alloy itself is deter-
mined by this resistance and is itself only an in-
dicator. It can be regarded as a measure of the
limit of elastic deformation in the microregions of
the material in question. Consequently, it is not
only the yield point of annealed alloys but also the
degree of second-type distortions (&a/a) which
must be used as the characteristics of the individual
strength properties of crystals. Thus the absolute
value of the strength properties of alloys in the
strain-hardened state depend not only on the appear-
ance of a fine crystalline grain structure but also
on the properties of the metal crystals themselves
in the initial as-annealed state.
In papers [1-3, S] a different level of hardness
was achieved in iron alloys by varying the
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
Fe+2,5 Ni 300
-~_ 280
250
~ ?u0 ~
Temperature
dependence N
Temperature
dependence
da
72n
100 200 300 400 500
FIG. 1. Dependence of hardness HV, yield point as, size
of the fields of coherent scattering D on tempering tem-
perature for the quenched alloy Fe + 25 % Ni;
temperature dependence of yield point as (t)
and hardness HV (t).
as
a
24
Crystal properties and grain substructure I
24,
2,0
? /5
x 1.2
c 1 0
28
40 50 50 70 80
o (t), kg/mm'
FIG. 2. Relation between second-type distortions
Aa/a and yield point for the alloy Fe + 25 % Ni.
properties of the crystals by alloying the iron with
various different elements or changing the concen-
tration of one of them. It is, however, possible to
obtain different properties in the same material
without change of chemical composition, by varying
the temperature. The property which interests us,
yield point, is known to be dependent on tempera-
ture. Therefore, if the strength characteristics of a
strain-hardened metal are measured at various dif-
ferent temperatures, they should vary with the
temperature parallel to the variation in the yield
point of the annealed metal as long as the substruc-
ture of the grain remains unchanged with temperature
variation. The extent of the second-type distortions
which occur as a result of deformation at various
different temperatures should vary in exactly the
same way. Besides this there should be a definite
relationship between the is/a value and yield point
at the various different stages of softening. Of
course, the beginning of the reduction in second-
type distortions on heating will occur at the tem-
perature at which the elastic deformation limit of
the crystals becomes less than the residual elastic
deformation of the microregions which arise after
strengthening. At this temperature the crystals are
not in a position to withstand such a degree of
microstresses as arises after deformation at lower
temperatures. Stress relaxation then occurs.
Consequently the extent of second-grade distor-
tions determined after the specimens have been
heated up to various different temperatures should
serve as a characteristic of the maximum elasto-
plastic deformation which the crystal of the material
can maintain at the temperature in question. The
Aa/a curve after heating up to various temperatures
(determined at 20?C) should reflect the temperature
dependence of the elastic limit of the material.
It is the aim of the present work to study the in-
fluence of variation of crystal properties due to
temperature changes, on the strength characteristics
of metals after strain-hardening and on the extent of
elastic deformations in microregions (second-type
distortions).
The binary alloys Fe + 25 % Ni and Fe + 1.15 % Si
were used for the investigation. The first was
strengthened by quenching and the other by cold
rolling with a total reduction of 50%. The reason
for choosing the alloy Fe + 25-0 Ni as an object
for investigation was the fact that when it is tem-
pered to 450?C almost complete relief of second-
type distortions is observed with practically no
change in the size of the regions of coherent
scattering [6].
The principal methods used for the investigations
were those of X-ray diffraction analysis based on the
study of the width of interference lines. The width
of interference lines (110) and (220) were deter-
mined. The X-ray photographs were made in FeKa
radiation. The magnitude of the type II distortions
and the size of the regions of coherent scattering
[8] were determined from the broadening effect of
FIG. 3. Tempe
yield p
the interferenc
characteristics
(1) yield poi
hardness (HV)
stages of softe
(2) temperatt
which, in that
(t), HV (t) resp
ening and after
Fig. 1 show:
fine structure c
tore dependent
HV (t) for the I
strain-hardened
same illustratic
sured at 20? aft
various differer
The temperat
yield point are
aS,HV measure,
25 kg/mm' in yi
that measured a
tempered at the
ing variation.in
of the variation
the same. This i
there is practic
specimens temp
tures when this
in these experir
yield point refit
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
Crystal properties and grain substructure I 119
Initial position
C5- j'- quench
~,_ -\~--- Initial position
temper. 4S0?C
o
.. Initial position
quench
change in the substructure on heating. Actually, in
00 the alloy Fe + 25 % Ni investigated the substructure
85 of specimens heated to 450?C remains practically
80 unchanged, the D value remains the same. This is
7S E also true of yield point.
70 The following experiments were carried out on
6S ~` the same alloy. After strengthening by quenching
60 o the specimens were tempered at 430?C to relieve
SS the greater part of the second-type stresses. The
50 temperature dependence of the yield point of speci-
4S mens which had 1 b
100 200 300 400 ,500 ?C
FIG. 3. Temperature dependence of UTS (GB (t)) and
yield point for the alloy Fe + 25 % Ni.
the interference lines. The following mechanical
characteristics were determined:
(1) yield point (os), UTS (aq) and Vickers
hardness (11V) after strain-hardening and at various
stages of softening;
(2) temperature dependence of as, aB and HV
which, in that work, were referred to as as (t), aB
(t), HV (t) respectively, in two states: after strength-
ening and after annealing.
Fig. 1 shows the variations after heating of the
fine structure characteristics (Aa/a, D) the tempera-
ture dependence of yield point as (t) and of hardness
NV (t) for the binary alloy Fe + 250;o Ni, previously
strain-hardened by quenching. For comparison the
same illustration shows the as and IN values mea-
sured at 20? after specimens had been tempered at
various different temperatures.
The temperature dependence characteristics of
yield point are very different from the changes in
as,11V measured at 20?C. There is a difference of
25 kg/mm' in yield point measured at 450?C and
that measured at 20?C in a specimen which had been
tempered at the same temperature. The correspond-
ing variation,in hardness is 80-90 units. The course
of the variation in 9a/a,a5 (t) and //h? (t) is practically
the same. This is confirmed by Fig. 2. The fact that
there is practically no change in the yield point of
specimens tempered at various different tempera-
tures when this is mca .:rrd at 20'C should mean that
in these experiments the nature of the change in
yield point reflects in ti ::,.tin. the nature of the
previous y een tempered at 4300C
was found to coincide with the as (t) dependence
of non-tempered ones. These data are in agreement
with conclusions expressed earlier that the pres-
ence of second-type distortions does not in itself
cause an increase in the resistance of the metal
to deformation.
The temperature dependence of UTS aB (t) of
alloys which have been quenched and first tempered
(Fig. 3) has the same form as that of as (t). The
slight divergence of the as (t) and aB (t), in the
tempered and non-tempered specimens appears to be
due to the small variations in the size of blocks
which occur as a result of an hour's tempering at
430?C.
The alloy Fe + 25 % Ni is particularly suitable
as an object of investigation. A number of experi-
ments can be carried out on it which, in our opinion,
make particularly clear the role of second-type
distortions in strength hardening [6] and the con-
nexion between Aa/a variations after various differ-
ent heating temperatures and the temperature depend-
ence of yield point. This alloy has however, the
disadvantage that it is not possible to bring about
softening to any degree by heating, due to the
rather low temperature for the commencement of the
reverse a -+ y transformation. Austenite which is
formed at above 460?C transforms to martensite
even with very slow cooling. It was not herefore
possible to establish on this alloy whether there
was any connexion between Aa/a and as (t) in the
annealed specimen.
Experiments similar to those carried out on the
binary alloy Fe + 25 % Ni were also done on the
alloy Fe + 1.15% Si. After the iron silicon alloy
had been strengthened second-type distortions
Aa/a = 1.75 x 10-', arose which did not vary when
heated to 300?C. Reduction in the Aa/a value
takes place at much higher temperatures; after
heating at 500-600?C it is 0.5 x 10-'. The regions
of coherent scattering start to grow at exactly the
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
100 300 500 700
Heating temperature ?C
FIG. 4. Variation in the hardness characteristics and
structure on heating in the alloy Fe + 1.15 % Si:
o- hardness (HV) of deformed alloy at 20? after
heating to various different temperatures;
7 - hardness HV (t) of annealed alloy at various dif-
ferent temperatures;
- hardness of deformed alloy at various different
temperatures, found experimentally (upper curve);
calculated values for the hardness of deformed
alloy.
same temperatures as the second-type distortions
start to decrease (Fig. 4).
After comparing the data for the change in hard-
ness of deformed specimens measured at 20?C after
heating at various different temperatures, with the
temperature dependence of hardness, we can see
that there is no change in the HV and HV (t) values
when heated to 300?C and they coincide. The change
in HV (t) is greater at higher temperatures than in
HV. This difference becomes more apparent as the
temperature increases and at 700? it is a 100 Vickers
unit.
Determination was also made of the temperature
dependence of the hardness of specimens first an-
nealed at 750?C. There was little change in the
hardness of annealed specimens when heated to
300?C and a sharp drop from 135 to 25 HV in the
350-700?C. The temperature dependence of the
hardness of previously annealed specimens indic-
ates the nature of the reduction in the resistance
to deformation due to change in the properties of
Crystal properties and grain substructure I
1u b D, i
2.0
1.5
I la
1.2
T.\ J 0.8
the crystals with temperature. In this range of
temperatures the structure of the specimens should
not undergo any kind of change (as they were pre-
viously heated to 750?) and therefore it should not
/01) 300 500 700
Heating temperature ?C
FIG. 5. Hardness, second-type distortions, size of
regions of coherent scattering in alloy Fe + 1.15 %
Si deformed at 20?, after heating to various differ-
ent temperatures (unfilled squares, triangles, cir-
cles); the same for alloy deformed at various differ-
ent temperatures (filled squares, triangles, circles).
be dependent on HV changes.
The curve for the variation in HV measured at
20?C, in deformed specimens heated to various
different temperatures, does on the other hand only
reflect the changes in the micro - and submicro-
structure of the grain which occur as the tempera-
ture is increased. If the temperature dependence
of the hardness of strain-hardened specimens is
measured, it will be found that at each temperature
changes in the substructure of the grain and the
properties of the crystals also have an effect on
hardness.
On this basis we plotted a "theoretical" curve
for the temperature dependence of hardness HV (t)
for cold deformed alloy. We used the curve for the
temperature dependence of the hardness of an an-
nealed alloy and that for the variation in hardness
measured at room temperature (HV) after heating
a strain-hardened alloy to different temperatures.
The reduction in hardness at each temperature due
to change in the properties of the crystals can be
found from
reduction is
substructure
tent of the
The results
and indicat
obtained an
obtained ex
If it is tr
given tempt
the crystal
substructur
tion at elev
than the re:
room tempe:
temperature
elevated te:
the Aa/a vi
deformed at
temperature
These ex
specimens
750?C. 1t he
temperature
results wer
changes in
ing tempera
hardened a!
I. V.M. GC
G.V. Kt
Fiz. me
2. G.V. Kt
Probl. r,
228 (19.
3. G.V. Kt
4. L.S. Mc
(Fine s,
Metallu
5. V.M. K:
Fiz. me
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
;;,und from the first curve, and from the second, the
reduction in hardness due to coarsening of the grain
substructure. Put together they should give the ex-
tent of the decrease in hardness of the heated alloy.
The results of the calculation are given in Fig. 4
and indicated by the black triangles. The values
obtained are in very good agreement with the curve
obtained experimentally (unfilled triangles).
If it is true that resistance to deformation at any
liven temperature is determined by the properties of
the crystal of the material and the nature of the grain
substructure, then the resistance to plastic deforma-
tion at elevated temperatures should be equal or less
than the resistance of specimens strain-hardened at
room temperature and tempered at various different
temperatures. The Aa/a value after deformation at
elevated temperatures should be less than or equal to
the sa/a value obtained after heating specimens
deformed at room temperature to a corresponding
temperature.
These experiments were carried out on Fe-Si
specimens which had been deformed at 330, 480 and
750?C. 1f hen they were rolled under cold rolls their
temperature was slightly reduced, by 40-60?C. The
results were compared with data regarding the
changes in Aa/a, D and HV in dependence on temper-
in temperature of specimens previously strain-
hardened at room temperature (Fig. 5).
The experimental data obtained are in very good
agreement with the hypotheses put forward.
Second-type distortions, which reflect the pro-
perties of crystals, vary on heating parallel with
the temperature dependence of the yield point of
an annealed or strain-hardened material, so long as
the substructure remained unchanged in the temper-
ature range investigated. The change in yield
point or hardness observed at 20?C in strain-
hardened specimens heated to various different tem-
peratures, is the result of a change in substructure
(softening) which has occurred during heating. The
strength of metals and alloys strain-hardened at
various different temperatures is determined by the
properties of the crystals at the temperatures in
question and by the nature of the micro - and sub-
microstructure of the grain which arises upon this.
T,,,,.cI,eI-,l by V.
I. V.M. Golubkov, V.A. I1'yina, V.K. Kritskaya,
G.V. Kurdyumov and M.D. Perkas,
Fiz. metal. metalloved., 5, 465 (1957).
2. G.V. Kurdyumov, M.D. Perkas and A.Ye. Shamov,
Probl. metalloved. i fiz. met., 4, Metallurgizdat,
228 (1955).
3. G.V. Kurdyumov, Zh. tekh. fiz., 24, 1254 (1954).
4. L.S. Moroz, Tonkaya struktura i prochnost,stali
(Fine structure and strength of steel),
Metallurgizdat, 85 (1957).
5. V.M. Kardonskii, G.V. Kurdyumov and M.D. Perkas,
Fiz. metal. metalloved., 7, 752 (1959).
6. G.V. Kurdyumov, M.D. Perkas and L.G. Khandros,
Fiz. metal. metalloved., 7, 747 (1959).
7. A.I. I1'yiaskii, V.M. Kardonskii and M.D. Perkas,
Fiz. metal. metalloved.,
9, 294 (1960).
8. G.V. Kurdyumov and L.I. Lysal;,
Zh. tekh. fiz., 17, 933 (1947).
9. G.V. Kurdyumov,
Metalloved. i term. Or. met.,
10, 22 (1960).
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
122
THE INFLUENCE OF CRYSTAL PROPERTIES AND GRAIN SUBSTRUCTURE ON HARDNESS
11. IRON AND NICKEL*
V.M. KARDONSKII, G.V. KURDYUMOV and M.D. PERKAS
Institute of Metallography and Metal Physics,
Central Research Institute of Ferrous Metallurgy
(Received 26 August 1960)
The width of X-ray diffraction lines and the hardness of polycrystalline specimens in the annealed
and strain-hardened states have been measured at 20 and - 180?C. Strain-hardening was achieved by
plastic deformation at both temperatures.
Variation of tempering temperature causes the same degree of change in the hardness of strain-
hardened and annealed materials. The difference in the hardness of strain-hardened and annealed
metals remains the same at both temperatures; it increases with the extent of fragmentation of the
substructure of the grain.
The experimental results illustrate the additivity of the effect of the two factors on strength;
crystal properties and grain substructure.
The resistance of a strain-hardened material to
deformation is determined by the individual properties
of the crystals and the changes in the micro- and
substructure of the grain which occur on the strain-
hardening [1-4]. The yield point of the initial mater-
ial and-the magnitude of second-type distortions
(elastic limit of the microregions) of the material
strain-hardened to saturation, may be used as the
characteristics of the crystal properties. According
to experimental data [5], the yield point of an un-
strengthened material is defined by the resistance
which encounters a sliding dislocation on a surface
free of dislocation.
Crystal properties vary considerably with the
degree of alloying and temperature. Yield point (as)
is known to be highly dependent on temperature
below 20?C in metals with a body-centred cubic
lattice or solid solutions on their base. In metals
with a face-centred cubic lattice as hardly varies at
all when the temperature is reduced right down to
- 200?C. To assess the role of crystal properties
and the substructure arising during strenghtening,
on the increase in the resistance of a material to
plastic deformation it seemed to us that it would be
interesting to investigate the fine structure and
mechanical properties of metals which had been
* Fiz. metal. metalloved., 11, No. 4, 615-619, 1961.
strengthened at temperatures below + 20?C. Iron
and nickel were selected for the investigation as
these metals are very different in the nature of the
temperature dependence of their yield point below
20?C. The strain-hardening was achieved by com-
pression in a 100-ton press at 20 and - 180?C.
The main method of examination used was X-ray
diffraction analysis based on a study of the width
of interference lines; X-ray photographs were made
in FeK radiation at + 20 and -180?C*. Vickers
hardness (HV) was determined at + 20 and -180?C.
After 1 hr anneal at 700?C the iron had a hardness
of 65 HV at 20?C and the width of the interference
line (220) was 11.0 x 10-' rad. When the tempera-
ture of the annealed specimen was reduced to
-180?C hardness increased from 65 to 185 HV. At
the same time there was practically no change in
the width of the interference line measured at low
temperature, it was B (220) = 11.6 x 101 rad.
The iron specimen then underwent 30 per cent
deformation at -180?C. Hardness increased from
185 to 220 HV and the width of the line (220)
increased from 11.6 to 31 x 10-? rad. After the spe-
cimen had been heated from - 180 to + 20? the
width of the line reduced from 31 to 22 x 10-' rad
* Deformation, during which the temperature of the
specimens increased by 15-20?C, was carried out in
liquid nitrogen.
and hardness
cooling to -
temperature,
width of the
(Figs. 1, 2).
The increa
annealed spe
whole be attr
ties with reds
changes shou
measurement:
The increase
strain-harden.
creation of gr
increase in tl
10-' rad is dt
distortions ar.
When the at
room temperat
hardness due
a result of elc
ence in the ht
deformed spec
the same, as i
does not appe
to + 20?C. The
ference lines
- 180 to + 20?
type distortior
ties. In other
arise as a rest
cimen at - 18,
to room temper
duction in the
of the interfere
[6, 7] when sp
metals were he
It is interes
of the deforme,
hardness to in,
despite the fac
tortions was rc
heated to 20?C
The iron spe
of 30 a at + 20
85 HV and the
11.0 to 19.8 x
specimen was
to 200 HV. It i
of the iron at -
more dispersed
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
and hardness from 222 to 98 HV. After a second
cooling to - 180? hardness measured at the same
temperature, again increased to 220 HV and the
width of the line remained the same as at + 20?C
(Figs. 1, 2).
The increase of 120 units in the hardness of the
annealed specimen when cooled to - 180?C can as a
whole be attributed to the change in crystal proper-
ties with reduction in temperature. No structural
changes should occur. This is confirmed by the
measurements of the width of the interference lines.
The increase in hardness from 185 to 222 HY after
strain-hardening at - 180* is determined by the
creation of grain micro- and submicrostructure. The
increase in the width of the line from 11.6 to 31 x
10-' rad is due to the appearance of second-type
distortions and small regions of coherent scattering.
l~hen the strain-hardened specimen was heated to
room temperature there was a sharp reduction in
hardness due to the change in crystal properties as
a result of elevation of temperature. Here the differ-
ence in the hardness between the annealed and
deformed specimens at - 180 and + 20?C remained
the same, as the grain substructure created at -180?
does not appear to undergo any change when heated
to + 20?C. The reduction in the width of the inter-
ference lines when the specimens are heated from
- 180 to + 20? is mainly due to reduction in second-
type distortions due to changes in crystal proper-
ties. In other words, second-type distortions which
arise as a result of the strain-hardening of the spe-
cimen at - 180?C are partially relaxed when heated
to room temperature and in this case there is a re-
duction in the elastic limit. A reduction in the width
of the interference lines was observed in works
[6, 7] when specimens of a number of different
metals were heated to 20?C.
It is interesting to note that the second cooling
of the deformed specimen to -180?C caused the
hardness to increase once more from 98 to 220 HV
despite the fact that part of the second-type dis-
tortions was relieved when the specimens were
heated to 20?C.
The iron specimens also underwent deformation
of 30% at + 20?C. Hardness increased from 63 to
85 HV and the width of the interference lines from
11.0 to 19.8 x 10 rad (Fig. 3). When the deformed
specimen was cooled to -180?C hardness increased
to 200 HV. It is suggested that the strengthening
of the iron at - 180?C causes the creation of a
more dispersed substructure in the metal than that
HY ;or
deformation
ZZOr-r\B=J/0r/0 -rad
200
/80
/60
/UO
120-
/(91100
~G~rad
n
?
y-200
o-
p 6~ r
le
o ~r o`b ~ p
~~1 P
B=22.7?/0 rad
3=I/.0010'lad
After anneal
-/00 0 * 100 ?C
FIG. 1. Influence of deformation and temperature on
hardness and the width of line (220) in iron.
Deformation at low temperature.
which takes place after the same material has been
strengthened at 20?C and this in its turn causes
a greater strengthening effect.
A similar series of experiments was carried out
on the nickel specimens. Unlike the iron, in an-
nealed nickel hardness measured at - 180?C was
very little different from that measured at 20?C
(AHV = 15). When the nickel was deformed at
180?C there was a considerable strengthening
effect. Hardness increased from 65 to 160 HV and
the width of the lines from 11.4 to 23.9 x 10".
After heating to room temperature hardness decreased
from 160 to 140 HV and the width of the line (222)
remained practically unchanged. After a second
cooling to -180?C hardness measured at - 180?C
was 160 HV (Fig. 4).
Thus, in the nickel specimen, in which the
crystal properties change very little with reduction
of temperature, second-type distortions arising as a
result of strengthening at -180?C remain practic-
ally unchanged when heated to 20?C. As in the
case of iron, when the nickel was deformed at 20?C
the strengthening effect is less than with deforma-
tion at -180?. The effect on fine structure and
mechanical properties of cold plastic deformations
at + 20 and -180?C was also studied. Deformation
at -180?C has a greater strengthening effect than
at + 20?. The regions of coherent scattering are
smaller with the low temperature deformation than
after deformation at 20?C (Fig. 5).
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
124 _ Crystal properties and grain substructure: II
(After deformati.n ,
at /
.~/`~` .
.
5(2'D)= 22.2x/0 3rad l I - j
lY = 22/ After defonnationl-,
at /90
6(220)-13401'10 ,rad l i
B(220) -14 7 x /0-3rad I
After
annealing
i IAfter
Distribution curves for the intensity of line (220) in iron, obtained at two temperatures
after annealing and after low-temperature deformation.
After deformation I
- n
FIG. 3. Influence of deformation and temperature on hard-
ness of iron. Deformation at room temperature.
From these experimental data it can be seen that
the strain-hardened metals Fe and Ni behave differ-
ently with reduction of temperature. As was sug-
gested, there is a sharp increase in the resistance
of iron to plastic deformation at lower temperatures.
Here it is the variation of crystal properties, in. the
case of strain-hardening at -180?C, which makes
the greater contribution to the strength of the iron.
Submicro-imperfections of the structure play a
smaller part. Variations in the crystal properties of
the iron cause an increase of 35 HV units in its
jl
l
FIG. 4. Influence of deformation and temperature on
hardness and width of line (222) in nickel.
hardness after deformation at - 180?C. In nickel on
the other hand, crystal properties play a much
smaller part than that of the creation of submicro-
structural imperfections.
The greater strain hardening effect observed after
deformation at low temperatures appears to be due to
the fact that at these temperatures conditions are
favourable for the creation of a more dispersed
grain submicrostructure. The fact that in iron, in
which a sharp change of crystal properties is
observed when the temperature is raised from
-180 to + 20?C,
type distortions
firmed by the deF
I. G.V. Kurdyumo\
2. V.M. Golubkov,
G.V. Kurdyumov
Fiz. metal. mete
3. V.M. Kardonskii
Fiz. metal. mete
4. V.M. Kardonskii
and M.D. Perka:
11, 632 (1961).
I3e acing - g=227x/0 rad
_ After
i
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6
Crystal properties and grain substructure: 11
10 20 30 4'0 50 50
% Deformation
FIG. S. Dependence of hardness and size of the regions of coherent scattering in nickel
on the degree of deformation at various different temperatures.
- 180 to + 20?C, there is also a reduction in second-
type distortions (this is not found in nickel) is con-
firmed by the dependence of is/a on crystal
Translated by V. Alford
1. G.V. Kurdyumov, Zh. tekh. fiz., 24, 1254 (1954).
2. V.M. Golubkov, V.A. Il'yina, V.K. Kritskaya,
G.V. Kurdyumov and M.D. Perkas,
Fiz. metal. metalloved., 5, 465 (1957).
3. V.M. Kardonskii, G.V. Kurdyumov and M.D. Perkas,
Fiz. metal. metalloved., 7, 752 (1959).
4. V.M. Kardonskii, V.G. Kurdyumov, G.V. Kurdyumov
and M.D. Perkas, Fiz. metal. metalloved.,
11, 632 (1961).
S. W.G. Johnston and J.J. Gilman,
1. Appl. Phys.,
30, 129 (1959).
6. M.S. Paterson, Acta met.,
2, 823 (1954).
7. N.N. Davidenkov and B.I. Smirnov,
Izv. Akad. Nauk. SSSR, ser. fiz.,
3, 5, 623 (1959).
Declassified in Part - Sanitized Copy Approved for Release 2012/01/06: CIA-RDP80T00246AO16300130001-6