material science

Question 1

a regular repeating arrangement of atoms or molecules

Answer 1

crystal

Question 2

regular repeating atomic arrangement

Answer 2

crystalline lattice

Question 3

simplest crystalline structure, easy to distort, packing one of top of another to represent a cube of eight

Answer 3

simple cubic SC

Question 4

central atom surrounded by 8 other atoms in the surrounding planes harder and less malleable than hcp structures

Answer 4

body centered cubic BCC

Question 5

atoms at each corner and center of each cubic face, malleable good conductor

Answer 5

face centered cubic FCC

Question 6

atoms from one layer nest in the empty space between atoms of adjacent layer. Three layers of atoms mallable and good conductor

Answer 6

hexagonal close packed HCP

Question 7

what two basic structures are malleable and good conductors

Answer 7

Face centered cubic FCC and Hexagonal close packed HCP

Question 8

what the differences in FCC/HCP?

Answer 8

HCP is less ductile than FCC and they stack different

Question 9

what’s the moment a crystal begins to grow (liquid to solid)

Answer 9

Nucleation

Question 10

point in which crystals meet

Answer 10

grain boundaries

Question 11

what causes crystal growth

Answer 11

at solidification temperature

Question 12

crystal growth size depends on

Answer 12

nucleation points

Question 13

how to control grain size

Answer 13

fast and slow cooling

Question 14

fast cooling causes

Answer 14

more nucleation points and smaller grain/fine grain

Question 15

slow cooling causes

Answer 15

less nucleation points and larger grains

Question 16

grain impact on metal properties (larger grains)

Answer 16

lower strength, lower hardness, higher ductility

Question 17

all crystals have

Answer 17

some defect

Question 18

Two types of defects

Answer 18

natural and engineered -alloy

Question 19

______ ______ during production used to create materials with specific mechanical properties

Answer 19

manipulating defects

Question 20

three types of crystal defects

Answer 20

point defect, line or linear defect, planar defect

Question 21

whats the relationship between defects and plastic deformation

Answer 21

depends on dislocations for movement and plastic deformation during material forming operations increases the number of dislocations

Question 22

an atom is missing or in an irregular place in the crystalline lattice

Answer 22

point defects

Question 23

types of point defects

Answer 23

self-interstitial, interstitial impurity, substitutional, vacancies

Question 24

areas where atoms are out of position in a crystal, generated and move when stress is applied

Answer 24

linear/ line defects

Question 25

two types of dislocations

Answer 25

edge and screw

Question 26

____ dislocation with extra half plane of atoms

Answer 26

edge

Question 27

----- dislocation result of shear stress on a crystal structure

Answer 27

screw

Question 28

a distortion/disruption in the long range stacking sequence of a crystalline structrure

Answer 28

planar defects

Question 29

what are the three types of planar defects

Answer 29

stacking faults, twin boundaries, grain boundaries

Question 30

Two types of voids

Answer 30

Pores Cavitation

Question 31

Voids due to air bubbles trapped during solidification process

Answer 31

Pores

Question 32

Voids created due to shrinkage of material as it solidifies

Answer 32

Cavitation

Question 33

Small, homogenous region of impurity atoms clustered within the crystalline structure of a metal

Answer 33

Precipitates

Question 34

Materials change in shape due to applied load/stress

Answer 34

Deformation

Question 35

Temporary change in shape, self reveres when force is removed

Answer 35

Elastic deformation

Question 36

Permanent deformation of metal structure

Answer 36

Plastic deformation

Question 37

A metal made by combining it with one more different elements

Answer 37

An Alloy

Question 38

Purpose of an alloy

Answer 38

Increase strength and corrosion resistance

Question 39

Type of alloy Reactor vessel Recirc piping

Answer 39

Stainless steel

Question 40

Type of alloy Steam generator tubes Control rods drive

Answer 40

Inconel

Question 41

Type of alloy Pressure vessel Condensate feed water

Answer 41

Steel alloy Carbon and mild steel

Question 42

Type of alloy Fuel cladding

Answer 42

Zirconium

Question 43

Type of alloy Heat exchanger

Answer 43

Copper alloys Brass Bronze

Question 44

A measure of materials reaction to a applied force (compressive or tension)

Answer 44

Stress

Question 45

A measure of a materials deformation due to applied stress

Answer 45

Strain

Question 46

A measure of a materials ability to withstand applied load/stress without fracture/failure

Answer 46

Strength

Question 47

A measure of tensile stress (measure of materials ability to stretch)

Answer 47

Ductility

Question 48

An amount of energy per unit volume that a material can absorb before fracturing

Answer 48

Toughness

Question 49

An ability to resist deformation, penetration, indentation, and scratching

Answer 49

Hardness

Question 50

Types of stress that pulls a metal apart Plastic deformation by elongation

Answer 50

Tensile stress

Question 51

Force/stress that pushes a metal from both ends Plastic deformation by compression

Answer 51

Compressive stress

Question 52

Force or stress applied tangentially to the surface of the material in opposite directions

Answer 52

Sheer stress

Question 53

Angular displacement or twisting about the centerline/axis of the structure/material

Answer 53

Torque stress

Question 54

Prevent material failure Create uniformity of attachment Allow for thermal expansion and contraction without failure/ fracture

Answer 54

Torque limits

Question 55

Maximum compressive stress that, under gradually applied load, a material can sustain without failure

Answer 55

Compressive strength

Question 56

Maximum amount of tensile stress/force that a material can take before failure

Answer 56

Tensile strength

Question 57

The maximum force that can be applied to a clamping device without failure

Answer 57

Torque limits for clamping devices

Question 58

A drive function that put maximum values on the torque that a motor can deliver to prevent damaging the motor of motor failure

Answer 58

Torque limits for a motor

Question 59

Sudden break or cleavage of a metal without prior plastic deformation

Answer 59

Brittle fracture

Question 60

Characteristics of brittle fracture

Answer 60

No gross, permanent or plastic deformation of the metal in the region of the brittle fracture

Question 61

Used to alter physical and mechanical properties of metal without changing its shape

Answer 61

Heat treating

Question 62

Heat treating methods

Answer 62

Annealing Tempering

Question 63

Heat treatment process which alters the microstructure of a metal to change its mechanical properties Reduces hardness Increase ductility Eliminates internal stresses

Answer 63

Annealing

Question 64

Soften a metal for cold working

Answer 64

Annealing

Question 65

A heat treatment process that involves slow heating a metal to precise temperature below the critical point and slowly cooling to room temperature

Answer 65

Tempering

Question 66

Reduce hardness, improve ductility, increase toughness and strength thereby reducing brittleness

Answer 66

Tempering

Question 67

Common causes of material failure

Answer 67

Fatigue Corrosion Radiation induced embrittlement Chemical Work Harding

Question 68

Repetitive and redistribution of forces acting on a material will cause

Answer 68

Fatigue

Question 69

Combination of localized corrosion and fatigue failure Surface defects caused by localized corrosion like pitting

Answer 69

Corrosion fatigue

Question 70

Three factor that are necessary for stress corrosion cracking

Answer 70

Tensile stress Susceptible material Corrosion agent (oxygen/ chlorides)

Question 71

What two ways can neutron radiation impact crystals

Answer 71

Elastic interaction Inelastic interaction

Question 72

When the Atom decays and becomes a new element

Answer 72

Neutron inelastic interaction

Question 73

Radiation induced embrittlement increases and decreases what Hardness - Embrittlement - Ductility-

Answer 73

Increase Increase Decrease

Question 74

A sudden, extreme variation in temperature which causes tension/excessive stress in a material due to unequal expansion or contraction within the material

Answer 74

Thermal shock/ stress

Question 75

Susceptible materials to thermal shock

Answer 75

Reactor vessel in Bwr Reactor vessel, pressurize and steam generator for pwr

Question 76

Form of erosion caused by implosion of gas bubbles on a metal surface

Answer 76

Cavitation

Question 77

Chemical dissolution of surface oxides and metal accelerated by high velocity fluid and or flow impingement

Answer 77

Flow accelerated corrosion FAC

Question 78

Causes of flow accelerated corrosion

Answer 78

Dissolution of the oxide film Inadequate oxygen concentration/ph to sustain passive oxide film