MSE 2001

Question 1

Mechanical Property related to resistance of bending.

Answer 1

Elastic Stiffness/Elastic Modulus

Question 2

The mechanical property which measures the ease of which an object is permanently bent- Represented by lowercase sigma with a subscript y.

Answer 2

Yield Strength

Question 3

Mechanical Property for a metal which measures resistance to fracturing/breaking (K1c).

Answer 3

Fracture Toughness

Question 4

Mechanical Property related to amount metal can be stretched before being broken.

Answer 4

Ductility

Question 5

Thermal Property related to how much a material sags over time due to temperature change.

Answer 5

Creep

Question 6

Thermal Property related to limiting temperature which a material can be used at.

Answer 6

Maximum Service Temperature.

Question 7

Thermal Property related to amount which material expands when heated. Represented with lowercase alpha.

Answer 7

Thermal Expansion Coefficient

Question 8

Thermal Property related to the rate as which heat flows through material from hot area to cold area.

Answer 8

Thermal Conductivity

Question 9

Amount of heat is takes a material’s temperature to rise by given amount.

Answer 9

Heat Capacity

Question 10

Thermal Property related to time for material to melt after heat is first applied. Proportional to Thermal Conductivitiy/Heat Capacity.

Answer 10

Thermal Diffusivity

Question 11

Electrical Property related to ability for electricity to flow through material.

Answer 11

Electrical Conduction

Question 12

Material’s ability to limit and slow down rate of electrical flow through it.

Answer 12

Insulators

Question 13

Measures resistance to flow of electricity/slower rate.

Answer 13

Resistivity

Question 14

Property related to a materials response to an electric field being enforced upon it.

Answer 14

Dielectric Properties

Question 15

Materials with capacity to trap magnetic field permanently. Hard to demagnetize.

Answer 15

Ferromagnets/Ferrimagnets

Question 16

Measure of intensity of retained magnetism.

Answer 16

Remanence

Question 17

Idea that performance of material is limited to properties of materials.

Answer 17

Design Limiting Properties

Question 18

Force per area applied to a material when it is loaded in a certain way.

Answer 18

Stress

Question 19

Change of material orientation as a result of stress.

Answer 19

Strain

Question 20

Resistance to change of shape by stress when object is still elastic.

Answer 20

Stiffness

Question 21

Resistance to permanent deformation by stress

Answer 21

Strength

Question 22

Measured by mass per unit volume of material. Reflects mass and orientation of atoms in material.

Answer 22

Density.

Question 23

Stresses applied normal to face of material and on axis. They are in opposite directions.

Answer 23

Tension/Compression

Question 24

Stress parallel to face of object caused by torsion.

Answer 24

Shear Stress

Question 25

Applies to uniform shape that has equal/tensile/compressive force on all areas. Positive when pushing.

Answer 25

Hydrostatic Pressure

Question 26

Reaction to tensile stress measured as (change in length/length). Negative for compressive stress

Answer 26

Tensile/Compressive STrain

Question 27

Law that states that stress and strain are proprotionally linear up to yield strength and strain is recoverable. Measured as Stress =(Young's Modulus) * Strain

Answer 27

Hooke's Law

Question 28

Constant representing proportion between tensile/compressive stress and tensile/compressive strain.

Answer 28

Young's Modulus

Question 29

Constant telling proportion between shear stress and shear strain.

Answer 29

Shear Modulus

Question 30

Constant representing pressure and dilation (or strain from pressure).

Answer 30

Bulk Modulus

Question 31

What are the properties of silicone at low temperatures, high temperatures, and very high temperatures?

Answer 31

Low Temperatures- Insulator High Temperatures- Semi-Conductor Very High Temperatures- Metal/Conductor

Question 32

Happens when metal is cooled to certain temperature, causing zero electrical resistance

Answer 32

Superconductor

Question 33

Why does applying high pressure to a gas lead it to be liquified?

Answer 33

Assuming temperature is constant, high pressure causes distance between atoms in molecule to decrease, leading to more intermolecular bonds forming.

Question 34

What are the four scales of structures? What is the scale unit of each?

Answer 34

Macroscopic (10^-5) Microscropic (10^-6) Atomic (10^-9) Electronic (10^-10)

Question 35

What is the unit called indicating 10^-10 that is the smallest scale a material can be looked at?

Answer 35

Angstrom.

Question 36

What are the some characteristics of metals

Answer 36

o High Stiffness o When pure, soft/easily deformed.  Made strong through alloying while remaining ductile.  High fracture toughness. o Weaknesses- Reactive, corrode rapidly if not protected. o Good electrical/thermal conductors

Question 37

What are some characteristics of ceramics

Answer 37

o Structure- Crystalline of ionic and covalent bonds Attractive features. o Stiff, hard, and abrasion resistant. o Retain strength to high temperature and resist corrosion well. o Good electrical insulators. o Weaknesses- Brittle with low fracture toughness.  Low tolerance for stress.

Question 38

What are some characteristics of glasses?

Answer 38

o Lack of crystal structure lesses plasticitiy or deformation, meaning their hard and corrosion resistant.  Good electrical insulators and transparent to light. o Weaknesses- Brittle meaning low tolerance for stress.

Question 39

What are some characteristics of polymers

Answer 39

o Light in weight and low density. o Low stiffness. o However, strong b/c of low density meaning hard to deform. o Properties dependent on room temperature.  Tough/Flexible at room temperature, brittle at -4 C, rubbery at 100C of boiling water. * Some have useful strength about 150 C. o Easy to shape- Good for components that snap together. Strong bonds of sheets but weak bonds between sheets.

Question 40

What is an elastomer?

Answer 40

* Elastomers- Polymers with extremely low stiffness (500-5000 times less than metals as opposed to 50 times less in stiffness for polymers).

Question 41

What is a composite/hybrid material?

Answer 41

* Hybrids- Combination of Two or More materials o Carbon Fiber and glass. o Materials of nature (wood, bone, skin, etc.) are hybrids  Bones are mix of collagens (polymer) and hydroxyapatite(mineral). o High Cost as difficult to form and join.

Question 42

What are the different thermal processing and effects on steel?

Answer 42

 If slowly cooled from high temperature, steel will be soft and have low strength.  If rapidly cooled, steel is extremely hard and brittle.  However, if rapidly cooled and reheated to moderate temperature, good combination of strength and toughness.

Question 43

What is quantum mechanic theory

Answer 43

Electrons exhibit both wave and particle characteristics

Question 44

Schrodinger's Equation

Answer 44

Equation which describes electron wave motion in terms of energy levels and wave orientation.

Question 45

Pauli's Exclusion Principle

Answer 45

Each electron has unique set of four quantum numbers, due to the repulsion by each electron on each other if in close proximity.

Question 46

Ionic Bonds

Answer 46

Electron Transfer between two atoms with high difference in electronegativity. Attraction occurs between ionic core of nucleus and valence electron of other atom. Repulsion occurs when ions get closer together due to core electrons in each.

Question 47

Covalent Bonds

Answer 47

Created between two electronegative elements, meaning both attract ions. Develops through attraction between negatively charged shared electron and positively charged nuclei. Repulsion occurs when core electrons begin to overlap.

Question 48

Metallic Bonds

Answer 48

Solids composed of electropositive elements where electrons are shared by all atoms in compound. Valence electron forms cloud/sea of electrons surrounded by ion core. Attraction comes from positively charged ion core and negatively charged electron cloud. Repulsion occurs when electron shells of ion cores overlap.