Chapter 3 Flashcards
(34 cards)
Material characteristics that relate to the structure of a material, its formation from the elements out of which it is made, and its reactivity with chemicals , other materials, and its environment.
How’s it measured?
Chemical properties
Measured in laboratories and cannot not be determined visually.
What kind of property?
Characteristics of materials that pertain to the interaction of these materials with various forms of energy and with the human senses.
How measured?
Physical Properties
Either by senses or scales or other. No destroying necessary.
What kind of property?
Characteristics of a material that are displayed when a force is applied to the material.
How measure?
Mechanical Properties
Often require destruction of the material.
What are the 3 types of properties under the category Material Properties?
Why are these important?
Physical, chemical, and mechanical!
Used as selection factors to determine usability of material for app.
What is the ISO? What does it do?
International Standards Organization: set material property standards for use in industrynd set standard ways of measuring these properties.
What is ASTM?
List the other 4!
American Society for Testing and Materials
ANSI, CEN, DIN, and BSI
Do all materials use same property testing methods?
No, often the standardized way of measuring properties varies greatly between material types.
What is the energy needed to raise the temperature of 1 gram of a material by 1 degree celcius called?
Which materials have this?
Why important?
Specific Heat
All materials have a specific heat!
Good for estimating costs of heat treatment or cooling.
What is the property that explains the expanding of a material exposed to heat? Why could it be important?
Thermal expansion is important because an aplication could buckle and deform if not given enough room to expand in the presence of heat.
Must ALWAYS be considered in an engineering design.
What is the steady-state heat that will be transmitted by a material of given thickness and temperature differential per unit area?
Thermal Conductivity
What is an adiabatic chamber and what process is it used for?
It is a vessel that insulates so no heat can pass through; it is used in measuring thermal conductivity where the material has a hot copper block on top and water on the bottom.
What is Heat Distortion Temperature?
The temperature at which a material begins to change under stress.
Typically important for polymers.
What is the property called that explains attraction by a magnetic field?
Which 5 stable elements have this property?
Ferromagnetism
Iron, nickel, cobalt, gadolinium, and dysprosium.
What is a hysteresis loop and what does it reveal about a material on a graph?
It’s an italic “I” shape that reveals the magnetization properties of a material. The loop is skinny if easily gains and loses magnetism and wide if holds onto magnetism for longer.
All steels are ferromagnetic as long as they’re below the _ _ _ _ _ _ temperature, which includes that they cannot be _ _ _ _ _ _ _.
Curie point; austenitic (FCC)
Are all nickel and cobalt alloys ferromagnetic?
No!
What is the switch that makes a metalloid act like a metal on demand called? This thing led to the invention of computers!
A transistor!
Are valence electrons in metals stuck in place by bonds?
No, they move freely.
What property is associated with gravimetric physical properties?
Density/Porosity!
Color is measured by…
absorption of portions of the spectrum of electromagnetic radiation that is visible light.
True or False:
The Modulus of Elasticity is a material property.
How do you solve for it?
Sub-Solve
True! Crazy right?
Hooke’s Law: E = stress (sigma) / strain (epsilon)
stress = force / area :: strain = change in length / original length
Do you have to alter the material in order to get its modulus of elasticity?
You can, but you don’t have to! You can get it by measuring the velocity of sound in a material (who knew) using tranducers with ultrasonic sounds.
V = (E / roe) ^ 1/2
V = velocity, E = modulus, roe = density
Why is the Modulus of Elasticity considered a physical property?
Fun Fact: Modulus acts as the “spring constant” for steel.
Because, like density, it is a fundamental property of a material; Basically, doesn’t change with heat, shape, manufacturing technique, etc.
All what have a modulus of elasticity of 30 x 10^6 psi?
(20.6 GPa)
Steels!
Then copper w/ 18 x 10^6 & aluminum w/ 10 x10^6
