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Questions and Answers
What is the primary effect utilized by piezoelectric materials?
What is the primary effect utilized by piezoelectric materials?
Which material is commonly recognized as a piezoelectric material?
Which material is commonly recognized as a piezoelectric material?
Which effect describes the phenomenon of cooling when an electrical current is passed through dissimilar metals?
Which effect describes the phenomenon of cooling when an electrical current is passed through dissimilar metals?
What property distinguishes magneto-rheological fluids?
What property distinguishes magneto-rheological fluids?
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What do shape memory alloys do in response to temperature changes?
What do shape memory alloys do in response to temperature changes?
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The Seebeck effect is associated with which of the following?
The Seebeck effect is associated with which of the following?
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Which application is associated with magneto-strictive materials?
Which application is associated with magneto-strictive materials?
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What is typically the result of combining thermoelectric materials with a temperature gradient?
What is typically the result of combining thermoelectric materials with a temperature gradient?
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Which of the following are considered basic classifications of materials?
Which of the following are considered basic classifications of materials?
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Which property is NOT typically associated with metals?
Which property is NOT typically associated with metals?
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What is the primary characteristic of atoms in metals and their alloys?
What is the primary characteristic of atoms in metals and their alloys?
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Which of the following engineering materials is NOT classified as one of the three basic materials?
Which of the following engineering materials is NOT classified as one of the three basic materials?
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What does the term 'ductile' refer to in the context of metals?
What does the term 'ductile' refer to in the context of metals?
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How do the densities of metals generally compare to those of ceramics and polymers?
How do the densities of metals generally compare to those of ceramics and polymers?
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In terms of mechanical properties, what is a notable advantage of metals?
In terms of mechanical properties, what is a notable advantage of metals?
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Which of the following elements is commonly found in metals?
Which of the following elements is commonly found in metals?
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What is a key property of metals that allows them to conduct electricity effectively?
What is a key property of metals that allows them to conduct electricity effectively?
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Which of the following is NOT a classification of engineering materials mentioned?
Which of the following is NOT a classification of engineering materials mentioned?
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What does the term 'polymer' refer to?
What does the term 'polymer' refer to?
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In the context of composites, what is the matrix phase?
In the context of composites, what is the matrix phase?
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Which type of dispersive phase is typically used to enhance the yield strength of metals?
Which type of dispersive phase is typically used to enhance the yield strength of metals?
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What is a characteristic of smart materials?
What is a characteristic of smart materials?
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Composite materials aim to have which of the following benefits?
Composite materials aim to have which of the following benefits?
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Which material property is typically enhanced by incorporating ceramic dispersive phases?
Which material property is typically enhanced by incorporating ceramic dispersive phases?
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Study Notes
Electromechanical Materials - EME 205 - Lecture 1: Materials Classification
- Over 70,000 different kinds and grades of engineering materials exist, a number that is constantly growing. 1000 different materials are used to construct a single automobile.
Basic Material Classifications
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Three basic material types: Metals, Polymers, and Ceramics.
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Other important material groups: Composites, Semiconductors, Biomaterials, and Smart materials.
Classification of Materials
- Materials are grouped based on chemical makeup and atomic structure.
- Composites are made from two or more of the fundamental materials (metals, ceramics, and polymers).
1- Metals
- Composed of one or more metallic elements (e.g., iron, aluminum, copper, etc.) often along with small amounts of nonmetallic elements (e.g. carbon, nitrogen, oxygen).
- Atoms in metals and alloys are arranged in a very orderly manner, making them relatively dense compared to ceramics and polymers.
2- Polymers
- Include plastic and rubber, organic compounds based on carbon, hydrogen, and other non-metallic elements.
- These materials generally have low densities and are often flexible.
3- Ceramics
- Compounds between metallic and non-metallic elements, commonly oxides, nitrides, and carbides.
- Insulative to electricity and heat, and resistant to high temperatures.
- Typically hard but brittle.
Material Properties - Charts
- Charts (Figures 1, 2, 3, 4) illustrate the density, stiffness (elastic modulus), strength (tensile strength), and resistance to fracture (fracture toughness) of various materials across different categories (metals, ceramics, polymers, composites).
- Different materials have varying levels of these properties.
2 - Smart Materials
- Materials whose properties respond and adapt to changes in their environment (temperature, light, pressure, voltage, chemical compounds).
- These changes are generally reversible.
Classification of Smart Materials (Table) - Input/Output
- Table showing different types of smart materials, their input triggers, and corresponding responses (output).
i - Piezoelectric Materials
- Generate an electric charge when subjected to mechanical stress due to their crystalline structure.
- This effect is reversible; an electrical charge can also change the material's shape.
- Quartz is an exemplary piezoelectric material.
- Used as electromechanical transducers, actuators, and sensors.
ii - Magneto-strictive Materials
- Act as actuators and sensors in noise and vibration control, and infrastructural applications (as illustrated in Figure 26)
- Example: magneto-rheological fluid (MRF) which changes rheological properties when subjected to a magnetic field (apparent viscosity).
iii - Thermoelectric Materials
- Materials that transfer heat energy and electrical energy.
- Seebeck effect: a current is generated when a hot dissimilar metal is near a cold dissimilar metal, causing an electron transfer.
- Peltier effect: Passing a current through two dissimilar metals generates heat or cooling in the respective metals.
iv - Shape Memory Alloys
- Metals that change shape in response to temperature changes.
- They retain the original shape after the temperature change.
- Applications include certain medical devices.
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Description
This quiz covers the classification of engineering materials as introduced in EME 205. It explores the three basic types of materials: Metals, Polymers, and Ceramics, along with other important material groups. Dive into the properties and structures that differentiate these materials and their applications in engineering.
