Transcript Selection of materials

Application of Materials
Part II, Engineering materials
Structural strength
Strenth of
Materials
Stiffness
Reliability
Lifetime
Strength of materials
Properties determined at tensile/compression
tests

N
mm2
Fmax
Rm
FeH
Rp0,2
FeL
Permanent
elongation
Jäävpikenemine
Total elongation
Kogupikenemine
0
L, mm


A
At
Criteria for materials selection


plastic materials – yield strength (yield limit) –
Re, Rp (Rec, Rpc)
brittle materials – strength limit – Rm (Rmc), Rm/
Classification of materials (Re, Rp0,2)




low strength
medium strength
high strength
super high strength
< 250 N/mm2
250...750 N/mm2
750...1500 N/mm2
> 1500 N/mm2
Stress concentration
F
m
m
m ax
F
R
 max  2 m
t
F
F
t
R
Stiffness
Stiffness D = Ex K(geometric characteristic of crosssection)
At tension K = S (cross-section area)
At bending K = I (moment of inertia)
I = bh3/3
Modulus of elasticity
NormaalNormal
NihkeShear

MahtVolume


E=tg
E=
E



G=tg
G=
G=3/8E


K=tg
K=
K=E

Modulus of elasticity
Material
E, N/mm2 x 109
Diamond
WC
SiC
Al2O3
TiC
Mo & Mo-alloys
Co & Co-alloys
Ni & Ni-alloys
Steels
Cast irons
Cu & Cu-alloys
Ti & Ti-alloys
Zn & Zn-alloys
Al & Al-alloys
Sn & Sn-alloys
Graphite
Pb & Pb-alloys
Plastics
Rubbers
PVC
1000
450-650
500
390
380
320-360
200-250
130-230
190-210
170-190
120-150
80-130
45-90
70-80
40-50
30
15
1-5
0,01-0,1
0,003-0,01
Reliability (1)
Toughness – notch impact energy KU or KV, J
– fracture toughness KC, N/mm2  m1/2
KU
fracture
Ductile
Kiulise
pinna %%
TDBT
T
KHL
T
T’
TKHL
TDBT
DBT T
KHL
100
50
0
T50
T
55
2
10
R 0.25
TDBT – ductile-to-brittle transition
10
45
55
10
R 1.0
10
T  KU, KV – cold brittleness
T
5
KU
Reliability (2)
Influence of C, ordinary and alloying elements to KU
C
60
TDBT
T
KHL
KU
0,01% C
0,1% C
0,2% C
0,4% C
40
20
0,6% C
0
-20
0,01
0,03
0,05 %C
P
KU
-100
0
N
KU
norm
normal
0,03% P
600
elelteras
steel
N=0%
külmdef
cold
worked
teras
0,12% P
0
40
50
V
-20
Si
0
S
0,1% C
0,2% C
0,3% C
0
N = 0,01 %
o
80 TKHL
, CC -60 -40
DBT
TKHL
T
DBT
200
toomas
külmdef
cold
worked
o
+200 TTDBT
KHL, C
400
N = 0,1 %
0,03% P
-40
+100
+20 TKHL
, CC
DBT
o
-100
0,02
0,04
0,06 %S
0,12% P
-40
0
40
N = 0,01 %
o
80 TKHL, C
-60 -40
-20
0
-100
o
+20 TKHL, C
0,02
50
Si
V
0
Cr
50
Külmhapruslävi
T ,CT50, C
transition
Ductile-to-brittle
Reliability (3)
-50
-100
-150
Mn
Ni
-200
0
2
4
6
Legeerivate
elementide
%
%
of alloying
elements
8
0,04
0,06
Dependence of M toughness of
A-grain size
Reliability (4)
KU, KV
Purustustöö
Dependence of KU/KV on temperature
low
strength
Madaltugev
KU,
A U, JJ
15,4
14,0
12,6
11,2
9,8
8,.4
Kõrgtugev
high
strength
7,0
5,6
4,2
2,8
Temperatuur
T
2
3
4
5
6
7
no.
8 Grain
Tera nr.
Fine and coarse grain steels
a
b
T, C
T, C
1200
1200
1100
1100
1
A
1000
1000
Acm
900
800
A+T
800
A+F
AC1
A1
700
700
F
F+T
600
600
0
1 – killed steel
2 – rimmed steel
900
A3
0,5
1,0
2
1,5 C%
dA
dP
d
Influence of microalloying elements
140
2 2
ferrite,
size oftera,
Grain
Ferriidi
mm
120
100
V
Vanaadium
80
60
40
20
Ti
Titaan
Nb
Nioobium
0
0 0,02 0,04 0,06 0,08 0,10 0,12
Alloying elementide
elements, % %
Legeerivate
Plane strain fracture toughness K1c
At tension K1c
b
F
Coefficient of stress intensity
K max  max a [MPam1/2]
a
F
Material
WC
TiC
SiC
Al2O3
SiO2
Steels
-low carbon
-maraging
K1C, MPa 
m1/2
(E)
6 (680)
4 (440)
3 (420)
3 (320)
0,7 (100)
54
110-175
Fracture toughness K1c, MPa  m1/2
Relationship between K1c and yield
strength
Superplastic
steels
Lowalloyed
highly
tempered
steels
Maraging
steels
Precipitation
hardened
stainless
steels
Yield strength, MPa
Life time (1)
R
(R = min/max)
-1 – symmetric loading
Fatigue
a
b

Pingeepüür


R
F
Impactors:
- surface roughness
- stress state
- stress concentrations
N1
N2
N3
107
N
Steels N = 107
Nonferrous alloys N = 108
Life time (2)
Material
Plain carbon
steel
-strain
hardened
-annealed
Alloyed steel
Al-alloys
-wrought alloys
-cast alloys
Ti-alloys
Cu-alloys
Rp0,2,
N/mm2
-1,
N/mm2
275
475
1700
275
110
900
450
240
340
700
100
80
500
150
Life time (3)
Creep  = f(, T, t)
 low temperature T/Tm < 0.5
 high temperature T/Tm > 0.5
Impactors
 structure
750
 alloying (super creep alloys) – 
1.0 /1000
 TMT
Corrosion
Modes of corrosion
Chemical
in dry gases
in organic liquids
in water containing environments
Electrochemical
Biochemical
in melt electrolytes
Types of corrosion
a
b
c
d
e
f
g
h
i
a - ühtlane, b - ebaühtlane, c - valikuline, d - laiguline,
e - rõugeline, f - täpiline, g - pinnaalune, h - kristallidevaheline,
i - pinge korrosioon
Types of corrosion:
a – uniform
b – nonuniform
c – selective
d – spotted
e – pitting
f – dotted
g – under surface
h – intercrystal
i - stress
Chemical corrosion of metals (1)
2 Mg + O2 = 2 MgO
2 Fe + 3 O2 = Fe2O3
For protection
Voxide > Vmetal
Kui Voxide/Vmetal > 1 – Cd, Al, Ti, Zr, Zn, Ni, Cr, Fe
At high Voks / Vmet (1,2…2,0)  cracking
High temperature corrosion
T  1000 C – oxide layer  electroconductive
Chemical corrosion of metals (2)
Corrosion influencing parameters
 structure
 surface treatment
materials parameters
 internal stresses
 T



gas composition
velocity
environmental parameters
heating parameters
Chemical corrosion of metals (3)
Protection
all. el
base metal all. el.
base metal
 alloying (F
)
, rion  rion
oxide  Foxide
 coatings
 protective atmosphere (at heat treatment) (H2 +
N2 + H2O; CO + CO2 + N2; etc.)
Electrochemical corrosion of metals (1)
Moisture + H2S, Co2,
So2, NaCl 
electrolyte
metals  galvanic pair
Normal potential
E, V
-2,37
-1,66
-1,63
-1,18
Galvanic series
Normal condition
Mg
Al
Ti
Mn
-0,76
-0,74
Zn
Cr
-0,44
-0,40
-0,25
-0,14
0,13
+0,34
+0,80
+1,20
+1,50
Fe
Cd
Ni
Sn
Pb
Cu
Ag
Pt
Au
Sea water
Mg
Zn
Cd
Al
soft steel
Pb
Sn
Ni
brass
Cu
monel (Ni alloy
Cr-steel (13% Cr)
Ti
Cr
Ag
Au
Pt
Electrochemical corrosion of metals (2)
Microgalvanic pairs at steels
Atmosphere
Moisture
film
Metal
Electrochemical corrosion of metals (3)
Protection (1)

Selection of materials
Table: Allowed contacts of metals
I
Mg
II
Al
Zn
Cd
Group
III
Fe
plain
carbon
steel
Pb
Sn
IV
Ni
Cr
V
Ti
Cu-Ni
alloy
Stainless Cu-Zn
steel
alloy
Cr-steel Cu
Ag, Au
Protection (2)

Protective coatings
- metallic (less active metals (Cu, Ni, Sn, Ag) – up
to coating must be undamage; active (Zn, Co) –
protection up to end)
- paints, lubricants

other
- cathodic protection
- protector protection
- anodic protection
- corrosion inhibitors (high molecular matters)
Wear
Modes of wear
Mechanical
Corrosive-mechanical Adhesive
-abrasion
-erosion
-cavitation
-fatigue wear
-oxidizing wear
-fretting corrosive wear
Method for wear protection





hardening, thermo-chemical treatment
overwelding
surface alloying
coating (chemical, thermo-chemical, thermally
sprayed, PVD, CVD, mechanical)
selection of pairs (by adhesion)
Wear testing methods
a
b
F
F
I
c
d
F
2
1
Description
Sliding friction with or
without a lubrication
F
3
1
F
F
II
4
1
5
III
F
5
3
6
8
F
IV
7
1
6
Abrasive wear
3
F
I, II - libisev hõõrdumine määrimisega või ilma;
III - abrasiivne kulumine;
F
5
Rolling friction with or
without a lubrication
Material groups
Metals
Cermets
MCM
CCM
Ceramics
Glass-ceramics
GCCM
Composites
PCM
FRG
Polymers
MCM
CCM
PCM
GCCM
FRG
Metal composite materials
Ceramic composite material
Polymeric composite material
Glass-ceramic composite material
Fiber-reinforced glass
Glass
Specific strength of materials (1)
Material group
Metals and alloys
Plastics
Cast irons
Plain carbon
steels
Alloy steels
Al-alloys
Cu-alloys
Ti-alloys
Mg-alloys
PVC
PE
PC
Fiberglass
plastic EP
.
PC

kg/m3
7800
7800
7800
2700
8900
4500
1750
Rm
N/mm2
150…800
320…1000
460…1650
150…500
230…700
300…1450
150…335
1350
950
1050
1250
1250
10…25
20…40
35…80
30…90
80…170
Rm/
up to
10
13
21
18
8
32
20
8
14
Specific strength of materials (2)
Material group
Ceramics
Compo
-sites
Wood

kg/m3
3980
4240
3160
3220
3170
2700
Al2O3
TiO2
3Al2O3 2SiO2
SiC (-modif.)
Si3N4
Al-B (30%)
Al-B (50%)
Fiberglass plastic EP 1250
EC
Carbon-Carbon
composite
3-directions
Pine
550 II
Oak
690 II
Rm
N/mm2
300…400
70…170
110…190
450…800
500…1000
80
110
30…90
80…170
Rm/
up to
10
4
6
25
22
4
14
35 (2000C)
5 (3000C)
89
97
17
Basic physical and mechanical
properties of construction materials (1)
Property
Density, 
kg/m3 x 10-3
TS, C
Hardness
Workability
Tensile
strength Rm,
MPa
Compressive
strength Rmc,
MPa
Metals
2-6
(average.
8)
Low. 
High.
Sn232,
W3400
Average
Good
Ceramics
2-17
(average.
5)
Polymers
1-2
High 
4000
Low
High
Poor
Low
Good
 2500
 400
 120
 2500
 5000
 350
Basic physical and mechanical
properties of construction materials (2)
Property
Modulus of
elasticity, E GPa
Creep resistance
at high
temperatures
Thermal
expansion
Thermal
conductivity
Electrical
properties
Chemical
inertness
Metals
Ceramics
Polymers
40  400
150  450
0,001  3,5
Poor
Outstanding
-
Average 
High
Low 
Average
Average
(mostly
lowers then
t )
Average
Very high
Very high
Conductors
Isolators
Isolators
Low 
average
Outstanding
Good in
general
Thank you for attention
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