4250 ENGR
Advanced Materials Engineering
Lecture 8
Testing of Materials
Metallic Alloys
Dr. A. Keshavarz ENGR 4250U
Structure, Processing, & Properties
Properties depend on structure
ex: hardness vs structure of steel
(d)
Hardness (BHN)
600
500
400
(c)
(b)
(a)
4 m
300
200
30 m
30 m
100
0.01 0.1
30 m
Data obtained from Figs. 10.30(a)
and 10.32 with 4 wt% C composition,
and from Fig. 11.14 and associated
discussion, Callister 7e.
Micrographs adapted from (a) Fig.
10.19; (b) Fig. 9.30;(c) Fig. 10.33;
and (d) Fig. 10.21, Callister 7e.
1
10 100 1000
Cooling Rate (C/s)
Processing can change structure
ex: structure vs cooling rate of steel
Dr. A. Keshavarz ENGR 4250U
ASTM
ASTM International (American Society for
Testing and Materials International) is one
of the largest voluntary standards
development organizations in the world
Founded in 1898: American Society for
Testing and Materials
Rail breaks
2001
Dr. A. Keshavarz ENGR 4250U
ASTM International
ASTM
ANSI (1918: AESC) National body
ISO & IEC
BSI (1901),
DIN (1917) DIN476
AFNOR (1926),
JIST
Dr. A. Keshavarz ENGR 4250U
www.astm.org.
ASTM International is a not-for-profit
organization that provides a global forum
for the development and publication of
voluntary consensus standards for materials,
products, systems and services. ASTM
standards are accepted and used in research
and development, product testing, quality
systems, and commercial transactions
around the globe.
Dr. A. Keshavarz ENGR 4250U
Standards
6 categories
The Standard Specification, that defines the requirements to be
satisfied by subject of the standard.
the Standard Test Method, that defines the way a test is performed.
The result of the test may be used to assess compliance with a
Specification.
the Standard Practice, that defines a sequence of operations that, unlike
a test, does not produce a result.
the Standard Guide, that provides an organized collection of
information or series of options that does not recommend a specific
course of action.
the Standard Classification, that provides an arrangement or division of
materials, products, systems, or services into groups based on similar
characteristics such as origin, composition, properties, or use.
the Terminology Standard, that provides agreed definitions of terms
used in the other standards.
Dr. A. Keshavarz ENGR 4250U
Content of a test method
Descriptive title and scope of the test method
Date of last effective revision and revision designation
Person, office, or agency responsible for questions on the test method, updates,
and deviations.
The significance or importance of the test method and its intended use.
Terminology and definitions to clarify the meanings of the test method
A listing of the types of apparatus (and the specific device) required to conduct
the test
Safety precautions
Required calibrations and metrology systems
Environmental concerns and considerations
Sampling procedures. How are samples to be obtained. Number of samples.
Conditioning: temperature, etc, humidity, and Tolerance (engineering)
Preparation of samples for the test
Detailed procedure for conducting the test
Calculations and analysis of data
Interpretation of data and test method output
Report: format, content, data, etc
Accuracy, precision, bias, repeatability, reproducibility, and uncertainty of test
results
Dr. A. Keshavarz ENGR 4250U
ANNUAL BOOK OF ASTM STANDARDS
2007-2008 EDITION
Section 00
Section 01
Section 02
Section 03
Section 04
Section 05
Section 06
Section 07
Section 08
Section 09
Section 10
Section 11
Section 12
Section 13
Section 14
Section 15
Dr. A. Keshavarz ENGR 4250U
Index
Iron & Steel Products (8)
Nonferrous Metal Products (5)
Metals Test Methods & Analytical Procedures (6)
Construction (13)
Petroleum Products, Lubricants, & Fossil Fuels (6)
Paints, Related Coatings, & Aromatics (4)
Textiles (2)
Plastics (4)
Rubber (2)
Electrical Insulation & Electronics (4)
Water & Environmental Technology (7)
Nuclear, Solar, & Geothermal Energy
Medical Devices & Services
General Methods & Instrumentation
General Products, Chemical Specialties, End Use Products
STRESS-STRAIN TESTING
Typical tensile specimen
Typical tensile
test machine
Adapted from Fig. 6.2,
Callister 6e.
gauge (portion of sample with
=
length reduced cross section)
Other types of tests:
--compression: brittle
Dr. A. Keshavarz ENGR 4250U
materials (e.g., concrete)
--torsion: cylindrical tubes,
shafts.
Adapted from Fig. 6.3, Callister 6e.
(Fig. 6.3 is taken from H.W. Hayden,
W.G. Moffatt, and J. Wulff, The
Structure and Properties of
Materials, Vol. III, Mechanical
Behavior, p. 2, John Wiley and Sons,
New York, 1965.)
Elastic vs Plastic Behavior
Elastic behavior
Stress is linearly proportional to strain
= E where E = Youngs modulus
Plastic behavior
Permanent deformation
Stress and strain no longer linearly related
Dr. A. Keshavarz ENGR 4250U
PLASTIC DEFORMATION (METALS)
1. Initial
2. Small load
3. Unload
F
Plastic means permanent!
Dr. A. Keshavarz ENGR 4250U
linear
elastic
linear
elastic
plastic
Two Basic Quantities
Stress measures the force required to
deform or break a material
= F/A
Strain measures the elongation for a given
load
= (L-Lo)/Lo
Dr. A. Keshavarz ENGR 4250U
Yield Strength
Yield strength is an important engineering
parameter
It defines the stress at which plastic
deformation begins
Units are MN/m2 or MPa
Al 370 MPa
Steel 1500 MPa
Cu 490 MPa
Dr. A. Keshavarz ENGR 4250U
TENSILE STRENGTH, TS
Maximum possible engineering stress in tension.
Adapted from Fig. 6.11,
Callister 6e.
Metals: occurs when noticeable necking starts.
Ceramics: occurs when crack propagation starts.
Polymers: occurs when polymer backbones are
aligned and about to break.
Dr. A. Keshavarz ENGR 4250U
18
TENSILE STRENGTH, TS
01
Dr. A. Keshavarz ENGR 4250U
TENSILE STRENGTH - Steel
02
Dr. A. Keshavarz ENGR 4250U
Tensile Strength - Composites
03
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Tensile Strength - Fibers
04
Dr. A. Keshavarz ENGR 4250U