1. Metals and Its Alloys, their
crystalline structure and
properties
By: M. Sc. Arnaldo Valdés Carrazana.
WEB: https://acarrazana.coursesites.com
Email: acarrazana@salcc.edu.lc
Knowing the world of metals and alloys
means create solutions!

2. OBJECTIVES
• To analyze the most common alloys
used in engineering.
• To explain the influence of the crystalline
structure and the grains in the final
properties.
• To explain the main tests to obtain the
mechanical properties.
• To familiarize with the classification of
steels and its nomenclature according to
AISI , SAE and European codes.

3. Pure Metals in the Periodic Table.

4. Materials Classification Chart
Pure Metals and
their Alloys
Ferrous = (Base Iron)
• Pure Iron (Fe).
• Steels (Fe+C where
C<1.7%)
• Cast Iron (Fe+C
where C 1.7%)
Nonferrous = (No Iron)
• Aluminum (Al) and its
alloys (Silumin and
Duralumin)
• Copper (Cu) and its
alloys (Brasses and
Bronzes)
• Nickel (Ni) and its
alloys
• Precious metals (Au,
Ag)
• Refractory metals (Nb,
Mo, Ta, Ti).
Polymeric
•Thermoplastics
•Thermoset
•Elastomers
Ceramic
•Glasses
•Ceramics
•Graphite
•Diamond
Composite
•Reinforced plastics
•Metal-matrix composites
•Ceramic-matrix composites
•Sandwich structures
•Concrete
Metal: any of several solid mineral elements (such as iron, gold, silver, copper, etc.) that are malleable under heat or
pressure and can conduct heat and electricity; element yielding positively charged ions in watery solutions of its salts.
Ferrous, is an adjective used to indicate the presence of iron. The word is derived from the Latin word ferrum (iron).
Ferrous metals include steel, cast iron (Alloys Fe+C) and alloys of iron with other metals (such as stainless steel).
Non-ferrous is used to indicate metals other than iron and alloys that do not contain an appreciable amount of iron.
Alloy: The mix of two or more substances where at least one of them is a metal. For example Steels, Cast Iron,
Silumin, Duralumin, Brass, Bronze, etc. Pure metals have not practical use in industrial applications due the
low properties.

5. Brief Comparison
Ferrous Alloys (Base Fe)
• Magnetic (Because the Iron
presence)
• Heavy (Density=7.85g/cm3)
• Superficial Rust
• Color Dark Brown
•
•
•
•
Non Ferrous Alloys
(Base Al, Cu, etc.)
Non Magnetic
Light
No Superficial Rust
Color (Gray, Silver, Yellow,
Orange)

6. Identification of metals and Alloys

7. Internal structure.
• Macrostructure: Naked eye or low magnification.
• Microstructure: Optical Microscope (400-1500x)
• Substructure: Electron Microscope (Scanning or
transmission) up to 1000000x
• Crystal Structure: X-ray Diffraction
• Electron structure: Spectroscope
• Nuclear structure: Nuclear Magnetic Resonance (NMR)

8. Crystalline microstructure in Pure Metals.
Crystalline structure is a result of the an arrangement of atoms during the
solidification process.
a. Simple cube (SC)
b. Body Centered
cube (BCC)
c. Face Centered
Cube (FCC)
Note: In some metals and its alloys this structure changes not only
during the cooling process, and the final structure depends on the
cooling rate determining its final properties. For example Fe and Steels.

9. Stages during the Solidification in metals.
1. Nucleation: It begins at
foreign particles in melt.
3. Grain Formation: Interface
develops.
2. Crystal growth: Crystals
begin to grow from each.
4. Polycrystalline structure:
Grain growth is limited by
another grain, creating a
boundary between them

10. Crystalline Structure of Pure Metals.
All atoms are held in place by electromagnetic forces. If an external
force is applied the crystalline network can be broken if such force is
higher than the Yield Strength (YS).
A low strength level only cause a
temporal
deformation
called
(elastic deformation).
A higher strength lever (higher
than the Yield Strength of the
material will cause permanent
deformation
called
(plastic
deformation)
by breaking the
bunds between atoms.

11. Crystalline Structure of Alloys.
The crystalline structure of an alloy will be reinforced by the presence of
foreign atoms. This explains why in Industrial applications Pure metals
are not used. In other words a particular alloys (Example Steel) is
stronger than the pure metal (Fe).

12. Metal Properties
Mechanical
Properties
• Traction
• Compression
• Bending
Impact
(Toughness)
Technological
Properties
Hardness
•Brinell (HB)
•Rockwell (HR)
•Vickers (HV)
•
•
•
•
Weldability
Machinability
Malleability
Corrosion Resistance
Physical
Properties
•
•
•
•
•
•
Melting Point (Tm)
Density ( )
Thermal conductivity ( )
Specific heat (C )
Electrical resistivity ( )
Magnetic permeability ( )

13. Technological Properties:
Are those properties in relation with the Manufacturing Processes or Service.
The valuation is usually qualitative (Good, Regular, Bad). Quantitative
Methods also can be used.
• Weldability: The ability of an alloy to be welded well, using
simple procedures.
• Machinability: The ability to make parts using machining
cutting tools.
• Malleability: The ability of the metal to keep the shape after
the deformation without cracking in the edges.

14. Strength-Strain Diagram obtained from the Traction Test.
(MPa)
TS
(MPa
STEELS
Uniform
Elongation
)
Neckin
g
Al, Cu and its Alloys
T
S
Fractur
e
YS0.
Y
S
e
p
2
σ=E*δ
0.2 %
elastic
Eng.
Symbol
plastic
Parameter name
δ (%)
ISO
Symbols
p
Elastic Limit
Lower Yield Strength
Rp
Coupon Test
L -l
l
= 1 0
l0
l0
δ =
d0
d0-d1
d1
Re
y
USA
Symbols
Proportional Limit
e
Ys
y0.2
Conventional Yield Strength
Rp0.2
Ys0.2
t= u
δ
δ (%)
Ultimate Tensile Strength
Rs
UTS or TS
Relative Strain (Elongation)
A
δ
Poisson’s ratio (Estriction)
Z
=
d0
l0
l1
1MPa=10.19 kg/m2=145.04 psi

15. Typical values of Ultimate Tensile Strength, Yield Strength and
Elongation.
Metal or Alloy
TS (MPa)
Ys (MPa)
1725
205
65-2
185-285
40-200
60-3
90
35
45
90-600
35-550
45-4
220
70
45
140-1310
76-1100
65-3
320
58
30
Nickel Alloys
345-1450
105-1200
60-5
Titanium
275-690
140-550
30-17
Titanium Alloys
415-1450
344-1380
25-7
Molybdenum Alloys
90-2340
80-2070
40-30
Magnesium
160-195
90-105
15-3
Steels
Iron
Aluminum
Aluminum Alloys
Copper
Copper Alloys
Nickel
δ-
(%)
Magnesium Alloys
240-380
130-305
21-5
Note: (MPa “Mega Pascal” is the unit of strength in International System
and psi “pound per square inches” in Imperial System)

16. How to choose the filler metal for
welding?
The strength of the weld (Filler
Metal) during fusion welding,
should be equal or higher than
the metal to weld on (Base
Metal)
TSFM ≥ TSBM
This cannot be possible only
during Brazing or Soldering
since the nature of both FM
and BM are not the same.
(MPa)
TSFM
TSBM
YS
δ (%)

17. Coupon Test for Impact.
10mm
Pendulum
Impact
10mm
U or V
notch

18. Hardness Test.
Note: Hardness is important
for elements of machines,
not for structures or other.
a. Brinell Method.
Applied
Force
Coupon Test
Indenter
D
Di
b. Rockwell Method.

19. Physical Properties of several Metals and Alloys.
Metal or Alloy
Density ( )
(kg/m3)
Thermal conductivity Melting point (Tm)
( )
(⁰C)
W/(m·K) (t=20⁰C)
2712
204
659
Aluminum alloys
7700 - 8700
120 - 180
462-671
Brass - casting
8400 - 8700
Aluminum
990 - 1025
Red Brass
8746
159
1027
Yellow Brass
8470
115
930
Bronze - lead
7700 - 8700
850 - 1000
Copper
8930
385
1083
Gold
19320
318
1063
6800 - 7800
72
1530
Pure iron
Cast Iron
7850
Wrought Iron
7750
58
Gray (1370), Malleable
1360,
White (1370)
1450
Lead
11340
35.3
327
Nickel
8800
89
1453
Silver
10490
406
961
Solder 50/50 Pb Sn
8885
Non alloyed and low alloy steel
7850
53.6
1480
7480 - 8000
12.11 - 45.0
1430-1500
Tin
7280
63
232
Zinc
7135
115
419
Stainless Steel

20. Procedure for Calculation of Weight.
V: Volume (cm3)
: Specific Weight (g/(cm3)
A: Cross Sectional Area (cm2)

21. Examples.
Example 1: In a workshop there are 4 cranes (0.5Tn, 1.3Tn, 4Tn and 7Tn).
Which one cannot be use for lifting a steel slab with dimensions
(4000x1000x40mm)?
Solution: Calculating the weight of a steel slab:
Weigh (W)=Volume (V)*(Density)
W=(4M*1M*0.04M)*7850Kg/M3=1256kg=1.3Tn
Consequently cranes for (0.5 and 1.3) shouldn’t be used to lift the slab.
Example 2: Find out the weight of a similar slab made out of Aluminum.
W=(4M*1M*0.04M)*2712Kg/M3=433kg=0.4Tn
This can be lift with the (0.5Tn crane).
Example 3: How many times steel weigh more than Aluminum?
Solution:
7850/2712=2.89=2.9 times.

22. Steels Classification Chart
Steels = Fe + C where (C ≤ 2.14%)
Non Alloy Steels
(Plain Carbon) Steels
Low Carbon
C < 0.3%
Alloy Steel
Low Alloy
∑AE < 5%
Several types Si,
Si-Mn, etc
Cr-Mo
Medium Carbon
0.3% ≤ C < 0.5%
Medium Alloy
5%≤ ∑AE <10%
Ni (cryogenic)
High Carbon
0.5% ≤ C < 1%
Ultra High Carbon
1.0% ≤ C ≤ 1.7%
Cr-Mo-V
Ni (Maraging)
High Alloy
∑AE ≥ 10%
Cr-Ni (Stainless Steel Cr 12%)
Mn (Hadfield)
Mild Steel: Non Alloy and low carbon steel with C from 0.16 to 0.29%, which is used in 85% of all steel applications in the
world.

23. Application of Alloys
• Structures: Bridges, Buildings, Decks, Cranes,
Pipelines, Vessels, etc.
• Elements of Machines: Pistons, Bearings,
Shaft, Levers, etc. Parts that move.
• Devices: Appliances, Power tools, Furniture,
and other.
• Tools: Pliers, Screwdrivers, etc.
• Other: Pipes, Tubes, Fittings, Cables, etc.

24. Type of
alloy
Grade
Criteria of use
Type of supply
Examples
Good Weldability
Good Malleability
Good Machinability
Bars, Flats, Sheet
Metal, Beams,
Pipes
Structures;
Elements of machines were
hardness is not an issue.
Devices
For manufacturing Elements of machine.
For Machining + Heat Treatment to change
superficial hardness.
Regular Weldability (Not for manufacturing
welding)
Bars
Elements of Machines where
hardness is important.
HCNA
C≤0.5%
To withstand deformation and wearing.
Bad Weldability (Not for welding at all)
Bars
Tools
Springs
LCLA
C<0.3%;
∑AE<5%
Similar to LCNA but more Tensile strength,
Resistant to marine corrosion.
Bars, Flats, Sheet
Metal, Beams,
Pipes
LCNA
(C<0.3%)
MCNA
0.3≤C<0.5%
Steels
LCMA
C<0.3%
5%≤∑AE<10%
MCLA
and
MCMA
LCHA (Stainless)
LCHA (Hadfield)
Structures.
Thermal Resistance and Thermal stability (Cr, Mo) Pipes
Pipelines
Low temperature Applications
Pipes, plates
Pipelines
Special equipment.
Similar to MCNA but more hardness after heat
treatment.
Bars
Tools
Elements of machines
Rust Free
Luxury
Antibacterial
Pipes, Flats, Sheet
metal
Food containers
Chemical industry equipment.
Medical equipment
Casting
Tracks and rolls of caterpillars
and similar equipment.
Railroad.
Elements that get harder with working impacts

25. Influence of the carbon content in the
Mechanical Properties of the steel.
Elongation
(%)
30
Strength
(MPa)
1000
TS
500
15
YS
0
0
0.5
1
%C

26. Influence of the Alloy Elements in Hardness
and Impact) in Steels.

27. Examples of classification of steels:
1.
An steel with the following chemical
composition:
C=0.15%; P<0.002%, S<0.001%
Will be classified as Low Carbon Non Alloy (LCNA)
Steel .
Notes:
• Sulphur (S) and Phosphor (P) always are impurities in
steels (They are not Alloy Elements).
• Since C 0.15%, such steel is also called Mild Steel.
• Low Carbon Steels have GOOD WELDABILITY and
MALEABILITY.

28. Example 2:
2.
An steel with
composition:
the
following
chemical
C=0.15%; Mn=1%, Si=2.0% P<0.002%, S<0.001%
It Will be classified as:
Low Carbon and Low Alloy (LCLA) Steel with 3.0 % of
Alloy Elements.
LCLA Steels
Weldability.
usually
have
GOOD
or
ACEPTABLE

29. Example 3:
3.
An steel with
composition:
the
following
chemical
C=0.035%; Cr=18% and Ni=8%
Will be classified as:
Extra Low Carbon High Alloy (LCHA) Steel with (18 +
8)=26% of Alloy Elements. This is a typical Stainless Steel.

30. Identification of American Steels
According to the American Iron and Steel Institute (AISI) and the Society of
Automotive Engineering (SAE) Steels are identified as follows:
• A Four Digits code for Non Alloy, Low Alloy and Medium Alloy Steels. In
this case the last two digits represents the carbon content in percentage
while the first two digits the subgroup of steels according the alloy
system and application.
• A three digit code for High Alloy Steels (AISI) or five digits (SAE) where
the last two of the five represents the carbon content.
Notes:
1. In the following tables XX represents the carbon content in
percentage.
2. American steels are used worldwide.
3. Some countries like Japan use same nomenclature.
4. The most of European countries follow a totally different
nomenclature for example (Germany, Italy, Russia, France and
England).

31. Identification of NA, LA and MA Steels.
10XX
Plain carbon, Mn 1.00% max
11XX
Resulfurized free machining
12XX
Resulfurized - Rephosphorized free machining
15XX
Plain carbon, Mn 1.00-1.65%
13XX
Mn 1.75%
23XX
Ni 3.50%
25XX
Ni 5.00%
31XX
Ni 1.25%, Cr .65-.80%
32XX
Ni 1.75%, Cr 1.07%
33XX
Ni 3.50%, Cr 1.50-1.57%
34XX
Ni 3.00%, Cr .77%
40XX
Mo .20-.25%
44XX
Mo .40-.52%
41XX
Cr .50-.95%, Mo .12-.30%
Nickel-ChromiumMolybdenum Steels
43XX
Ni 1.82%, Cr .50-.80%, Mo .25%
47XX
Ni 1.05%, Cr .45%, Mo .20-.35%
Nickel-Molybdenum
Steels
46XX
Ni .85-1.82%, Mo .20-.25%
48XX
Ni 3.50%, Mo .25%
Carbon Steels
Manganese Steel
Nickel Steels
Nickel-Chromium Steels
Molybdenum Steels
Chromium-Molybdenum
Steels

32. 50XX
Cr .27-.65%
51XX
Cr .80-1.05%
50XXX
Cr .50%, C 1.00% min
51XXX
Cr 1.02%, C 1.00% min
52XXX
Cr 1.45%, C 1.00% min
Chromiumvanadium steels
61XX
Cr .60-.95%, V .10-.15%
Tungstenchromium steels
72XX
W 1.75%, Cr .75%
81XX
Ni .30%, Cr .40%, Mo .12%
86XX
Ni .55%, Cr .50%, Mo .20%
87XX
Ni .55%, Cr .50%, Mo .25%
88XX
Ni .55%, Cr .50%, Mo .35%
92XX
Si 1.40-2.00%, Mn .65-.85%, Cr 0-.65%
93XX
Ni 3.25%, Cr 1.20%, Mo .12%
94XX
Ni .45%, Cr .40%, Mo .12%
97XX
Ni .55%, Cr .20%, Mo .20%
98XX
Ni 1.00%, Cr .80%, Mo .25%
Chromium steels
Nickelchromiummolybdenum
steels
Siliconmanganese
steels
Nickelchromiummolybdenum
steels

33. Identification of High Alloy Steels.
Stainless Steels
SAE
AISI
Chromium–Manganese–Nickel Steels
302xx
2YY
Chromium–Nickel Steels
303xx
3YY
Chromium Steels
514xx
4YY
Chromium Steels
515xx
5YY
In the most of the European countries to identify high alloy steels the
chemical element is specified and after the amount except when is 1% for
example:
• 08Cr18Ni10T is a steel containing: 0.08%C, 18%Cr, 10%Ni and 1%Ti
• 06Cr12Ni25 is a steel containing: 0.06%C, 12%Cr, 25%Ni

34. Classification and application of Cast Irons.
Cast Iron (C
1.7%)
Non alloyed
Malleable
Gray
•
•
•
Ferritic
Whiteheart
Blackheart
Perlitics
Ferritic Perlitics
Vermicular
or Compact
Alloyed
Spheroidal
graphite (SG).
•
•
Perlitic
Note: Cast Iron is obtain out of
Casting process (in a mold)
and it is use for parts that have
to withstand vibrations and
compression loads.
White
Ordinary
ADI
Corrosion
High
Temperature
(Gray)
Ni
Si
Abrasive
Wear with
Impact
Antifriction
(Whites)
(Gray)
Cr
Cr-Ni
Cr-Mo
Ni
Si
(Gray)
•
•
•
Ni
Si
Al
Whites
•Cr
•
•
•

35. Applications of Copper Alloys.
Copper Alloys.
Brasses (Cu+Zn)
• Yellow (Cu-Zn)
• Leaded (Cu-Zn-Pb)
• Tin (Cu-Zn-Sn-Pb)
Bronzes (Cu+Sn).
• Phosphor (Cu-Sn-P)
• Lead Phosphor (Cu-Sn-Pb-P)
• Aluminum (Cu-Al-Ni-Fe-Si-Sn)
• Silicon (Cu-Si-Sn)
Note: Cooper alloys, are mainly used in pipes, tubes, valves, fittings,
antennas and in some cases friction bearings.

36. Identification of Copper Alloys.
Classification of copper alloys is determined by the Unified Numbering System (UNS),developed by the American Society for Testing
and Materials (ASTM), Society of Automotive Engineers (SAE) and the Copper Development Association (CDA).
The designation system uses five-digit numbers preceded by the prefix letter C.
The numbers from C10000 through C79999 define the wrought copper alloys.
Generic name
Major components
UNS designation number
Copper (Technically Pure)
>= 99.3% Cu
C10100…C15999
High-copper alloys
> 96% Cu but <99.3% Cu
C16000…C19999
Yellow Brasses
Cu-Zn
C21000…C28999
Leaded Brasses
Cu-Zn-Pb
C30000…C39999
Tin Brasses
Cu-Zn-Sn-Pb
C40000…C49999
Phosphor Bronzes
Cu-Sn-P
C50000…C52999
Lead Phosphor Bronzes
Cu-Sn-Pb-P
C53000…C54999
Copper-Phosphorous alloys
Cu-P, Cu-P-Ag
C55000…C55299
Copper-Silver-Zinc Alloys
Cu-Ag-Zn
C55300…C60799
Aluminum Bronzes
Cu-Al-Ni-Fe-Si-Sn
C60800…C64699
Brasses
Bronzes
Silicon Bronzes and Silicon Brasses Cu-Si-Sn
C64700…C66199
Other copper-zinc alloys
Cu-Zn-…
C66200…C69999
Copper-Nickels (Copper-Nickel-Iron Alloys)
Spinodal Bronzes
Cu-Ni-Fe
Cu-Ni-Sn
C70000…C73499
Nickel Silvers
Cu-Ni-Zn
C73500…C79999

37. The numbers from C80000 through C99999 define the cast copper alloys.
Generic name
Coppers
High-Copper Alloys
Brasses
Red Brasses and Leaded Red
Brasses
Yellow Brasses
Manganese Bronzes and Leaded
Manganese Bronzes
Major components
UNS designation number
>= 99.3% Cu
> 96% Cu but
<99.3% Cu
Cu-Sn-Zn
Cu-Sn-Zn-Pb
Cu-Zn
C80000…C81399
Cu-Zn-Mn-Fe-Pb
C86000…C86999
C81400…C83299
C83300…C84999
C85000…C85999
Silicon Bronzes and Silicon Brasses Cu-Zn-Si
Copper-Bismuth
Copper-Bismuth-Selenium alloys
Cu-Bi
Cu-Bi-Se
C88000…C89999
Tin Bronzes and Leaded Tin
Bronzes
Nickel-Tin Bronzes
Bronzes
C87000…C87999
Cu-Sn-Zn
Cu-Sn-Zn-Pb
Cu-Ni-Sn-Zn-Pb
C90000…C94500
C94600…C94999
Aluminum Bronzes
Copper-Nickels (Copper-Nickel-Iron Alloys)
Spinodal Bronzes
Nickel Silvers
Cu-Al-Ni-Fe
Cu-Ni-Fe
Cu-Ni-Sn
Cu-Ni-Zn-Pb-Sn
C95000…C95999
Copper-Lead Alloys
Cu-Pb
C98000…C98999
Special alloys
Cu-…
C99000…C99999
C96000…C96999
C97000…C97999

38. Conclusions.
• In industry Pure metals has not use, due the
low properties. Alloys offer better
properties due the inclusion of foreign
atoms in the crystalline structure.
• The chemical composition have influence in
the Mechanical, Technological and Physical
properties.
• The most common alloys
in our
environment will be (Steels, Brasses,
Bronzes and Cast Iron).

39. Internet References
•
•
•
•
•
•
Crystalline Structure.
NTD Resource Center
Wikipedia Encyclopedia
How Stuffworks
AISI / SAE Steel Identification Number
Stainless Steels International Standards.