Materials Science: Engineering, Processing, Design 2nd Ed

Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Introduction to Materials and
Processes
• A successful product – one that performs well, is good value
for money and gives pleasure to the user – uses the best
materials for the job, and fully exploits its potential and
characteristics
• Materials selection is not about choosing a material, but a
profile of properties that best meets the needs of the design
• Material and process are interdependent
• Materials and processes are grouped into families; each
family has a characteristic profile, the “family likeness,” which
is useful to know when selecting which family to use for a
design
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
1
Families of Materials
Polymers
Hybrids are a
(Macromolecules)
Ceramics
combination of materials
from other families
Members of a family have
common features:
• Similar properties
• Similar processing routes
• Similar applications
Figure 2.1
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Families of Materials
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
2
Examples of Each Material Family
Figure 2.2
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Figure 2.3
These attributes in addition to processing
characteristics, environmental impact
and typical applications make-up the
material’s property profile
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
3
Ceramics
•
•
•
•
•
•
Stiff – high E (Young’s modulus)
Hard – High Y (Strength)
Abrasion resistant
Good high temperature strength
Good corrosion resistance
Brittle – low KIC
Glasses
•
•
•
•
•
Hard
Corrosion resistant
Electrically insulating
Transparent
Brittle – low KIC
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Polymers (Engineering Plastics)
•
•
•
•
•
Light – low ρ
Easily shaped
High strength per unit weight (σ/ρ)
Lack stiffness – low E (50X less than metals)
Properties highly sensitive to temperature
Elastomers
• Lack stiffness – low E (500 – 5000X less than
metals)
• Able to retain initial shape after being stretched
• Relatively strong and tough
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
4
Metals / Alloys
•
•
•
•
Tough – high KIC
Stiff – high E
Ductile
Wide range of strengths depending on composition and
processing
• Thermally and electrically conductive
• Reactive – low corrosion resistance
Hybrids (Composites)
• Lightweight & Cost efficient
• Can be engineered
• Properties dependent on combination of
materials
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Classifying Processes
Choice of process is based on design
requirements:
• Material
• Shape, dimensions, and precision
• Number to be made
Process Families
Shaping - Shaping Primary Secondary
Joining
Surface
Treatment
Primary process
creates shapes
Secondary process
modifies shapes or
properties
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
5
Classes of Processes
Figure 2.4
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Primary Shaping
Hot Isostatic Pressing
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
6
Secondary Processes
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Joining
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
7
Surface Treatment
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Figure 2.7
Process selection involves matching
attributes of a process to design
requirements
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
8
Process-property Interaction
Effects processing can have
on material properties:
• Soft, stretchy rubber becomes hard and
brittle when vulcanized
• Annealing a metal increases its ductility
• Glass becomes bullet-proof through a
specific heat treatment
• Electroplating improves corrosion resistance
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Material Property Charts
Bar Chart
• Plot of one property for all
materials
of two properties for all
Bubble Chart • Plot
materials
• Gives an overview of physical, mechanical,
and functional properties
• Reveal aspects of the physical origins of
properties
• Tool for optimized selection of materials
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
9
Bar chart comparing stiffness (modulus)
between different material families
Figure 2.8
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Bubble chart comparing stiffness (modulus) and
weight (density) of different material families
Figure 2.9
Figure 2.9
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
10
Computer-aided Information
Management
Material and process records in CES
contain two types of data:
Structured
Unstructured
• Numeric
• Boolean (yes/no)
• Discrete
(low/medium/high)
• Text
• Images
• Graphs
• Schematics
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
Part of a record for a material, ABS; it contains
numeric data, text, and image-based information
Figure 2.10
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
11
Part of a record for a process, injection molding; the image
shows how it works, and the numeric and Boolean data and
text document its attributes
Figure 2.10
Materials: engineering, science, processing and design, 2nd edition Copyright (c)2010 Michael Ashby, Hugh Shercliff, David Cebon
12