MATEPRO Module 4

Question 1

In material selection, These materials were selected primarily because, not only did
they possess the desired properties and characteristics for
the intended functions of specific parts, but also they were
the ones that could be manufactured at the _________ cost

Answer 1

Lowest

Question 2

With regards to the structures of materials, the ____________ and _____________ of a material all boil down to its ______________ and _____________.

Answer 2

Properties and performance, structure and processing

Question 3

The number of protons in the nucleus
determines whether an atom will be
____________, ______________, or _______________
(low, high, intermediate)

Answer 3

Metallic, nonmetallic, or semimetallic.

Question 4

Combination of multiple atoms

Answer 4

Molecules

Question 5

Attractive Forces that hold the molecules together

Answer 5

Bonds

Question 6

Examples of primary bonds are _________, ____________, _____________

Answer 6

Ionic bonds, Covalent Bonds, Metallic Bonds

Question 7

Secondary bonds include _____________.

Answer 7

van de Waals forces

Question 8

Occurs when one or more electrons from an outer orbit are transferred from one atom to another.

Answer 8

Ionic bonds

Question 9

Ionic bonds generally have ____________ and ________________.

Answer 9

Poor ductility and low thermal/electrical conductivity.

Question 10

The electrons in outer orbits are shared by atoms to form molecules. Atoms achieve stability by sharing electrons with other atoms

Answer 10

Covalent Bonds

Question 11

Covalent bonds generally have ____________, ____________, and ________________.

Answer 11

Low electrical conductivity and high hardness, and high melting point.

Question 12

Occurs in atoms with very few valence electrons (1-3)

Answer 12

Metallic bonds

Question 13

Metallic bonds generally have ____________ and ________________.

Answer 13

High thermal and electrical conductivity.

Question 14

Occurs when a molecule is polarized: one side is more positive/negative than the other. The attraction of opposite charges without electron transfer

Answer 14

Van der Waals forces

Question 15

The various orderly configurations of the atoms when metals solidify from a molten state

Answer 15

Crystals

Question 16

Refers to the atomic arrangement when solidified

Answer 16

Crystal Structure

Question 17

The smallest group of atoms showing the characteristic
lattice structure of a particular metal. It is the building block of
crystal.

Answer 17

Unit Cell

Question 18

Topologically ordered, three-dimensional geometrical array of atoms composed of one or more repeating unit cells

Answer 18

Lattice Structure

Question 19

Lacks the periodically ordered arrangement
that is characteristic of a crystalline solid

Answer 19

Amorphous Structure

Question 20

When metals solidify, the atoms assume a _______________.

Answer 20

Crystal Structure

Question 21

A metal is normally made up of only____-______ or ______________
structure, but some can have multiple. These are called _____________ or ____________.

Answer 21

One crystal structure or lattice structure, allotropic or polymorphic

Question 22

For the crystal structure of metals, three basic atomic arrangements include the following (mention their characteristic)

Answer 22

1. Body-centered cubic (BCC); high strength
2. Face-centered cubic (FCC) ; high ductility
3. Hexagonal Close Packed (HCP); Brittle

Question 23

The change of a metal’s
lattice structure from one form to another

Answer 23

Allotropic transformation

Question 24

The top and bottom planes in the HCP structure

Answer 24

Basal Planes

Question 25

The modification of any of the three arrangements
by adding atoms of some other metals

Answer 25

Alloying

Question 26

Rank the three crystal structures of metal based on packed configurations (from most to least packed)

Answer 26

1. HCP
2. FCC
3. BCC

Question 27

When the crystal is subjected to an external force, it returns to its original shape when force is removed

Answer 27

Elastic deformation

Question 28

Also known as permanent deformation. If the force on the crystal structure is increased sufficiently that it does
not return to its original shape when the force is removed

Answer 28

Plastic deformation

Question 29

Ratio of the applied shearing force
to the cross-sectional area being sheared

Answer 29

Shear stress

Question 30

Properties that are uniform in all directions

Answer 30

Isotropic properties

Question 31

Properties that vary with direction

Answer 31

Anisotropic properties

Question 32

The combination of a slip plane and
its direction

Answer 32

Slip System

Question 33

Metals with 5 or more slip systems are __________.

Answer 33

Ductile

Question 34

List the number of slip systems per crystal (BCC, FCC, HCP)

Answer 34

BCC - 48 possible slip systems
FCC - 12 slip systems
HCP - 3 slip systems

Question 35

The strength of metals can be theoretically calculated
using ____________.

Answer 35

Molecular dynamics

Question 36

The ___________ strength of metals is found to be approximately one to two orders of magnitude __________ than the strength levels obtained from molecular
dynamics.

Answer 36

Actual, lower

Question 37

The reason for the discrepancy between the actual strength and theoretical calculation.

Answer 37

Defects and imperfections in the crystal structure

Question 38

When the material is raised to a high
enough temperature, the material will
attempt to _____________ to release some of that energy

Answer 38

Recrystallize

Question 39

The greater the amount of deformation, the ________ the recrystallization temperature

Answer 39

Lower

Question 40

When metals are plastically
deformed at temperatures below
their recrystallization temperature,
the process is called _____________ .

Answer 40

Cold Working

Question 41

If a material is deformed at
a temperature greater than
its recrystallization
temperature, the process is
called ____________.

Answer 41

Hot Working

Question 42

Materials composed of two or more different
elements, which tend to exhibit their own characteristic
properties

Answer 42

Alloys

Question 43

Consists of either a single crystal (for
pure metals) or polycrystalline aggregate (for alloys)

Answer 43

Grain / crystalline structure

Question 44

The initial stage of crystal formation

Answer 44

Nucleation

Question 45

The surfaces
that separate the individual
grains once they interfere with
and impinge upon one another

Answer 45

Grain boundaries

Question 46

The behavior of a single crystal or
a single grain is __________ .

Answer 46

Anisotropic