AMT- Materials Flashcards
(268 cards)
1
Q
Critical Temperature
A
The temperature in which metal structure cannot carry the service load it was designed to do due to softening from critical temperature.
2
Q
Hot working
A
Metal is worked above critical temperature
3
Q
Cold working
A
Metal is worked below critical temperature
4
Q
Rolling
A
Can be hot or cold working process. Metal is compressed between rollers.
5
Q
Forging
A
Metal is shaped by pressing, dropping, hammering at above critical temperature
6
Q
Extruding
A
Hot or cold process. Metal is forced through a die to create seamless superior product.
7
Q
Casting
A
Liquid state metals poured in mold to form shape. Widely used for parts such as turbine blades.
8
Q
Why is cold rolling preferred over hot rolling
A
Cold rolling makes the metal stronger due to work hardening
9
Q
Why does cold working provide a more accurate finish and dimensions
A
No thermal expansion
10
Q
What must be done to cold worked metal for further forming?
A
Annealing. Work hardening occurs when cold worked which makes the metal hard and brittle. Annealing relives the stresses and softens the metal so it can be worked further.
11
Q
What metals can be extruded?
A
Lead, tin, aluminum, alloys, copper, titanium, molybdenum, vanadium, steel
12
Q
What is an advantage of cold extruding?
A
No oxidation, good surface finish and mechanical properties
13
Q
What is a non-ferrous metal?
A
A metal that does not contain iron (Fe)
14
Q
What is an alloy?
A
A mixture of metallic solid solution composed of two or more elements that adhere to certain desired properties
15
Q
What advantages come from allowing aluminum?
A
Aluminum can exceed mechanical properties of some steel. Strength increased.
16
Q
Advantage of alloying molecular-wise
A
Stops dislocations of molecules from spreading. Resist deformation.
17
Q
Identify: AA 1140-H14
A
AA- Aluminum Association
1-Commercially pure Aluminum
1- Alloy mod once
40- 40 points above 99% pure (99.4%)
H1-Alloy hardened by working
4- Worked to harden to one half of potential
18
Q
Temper designations
O
A
Annealed
19
Q
Temper designations
H1
A
Strain hardened by cold working
20
Q
Temper designations
H12
A
Strain hardened by cold working
2 indicates 1/4 hardness
21
Q
Temper designations
H14
A
Strain hardened by cold working
4 indicates 1/2 hardness
22
Q
Temper designations
H18
A
Strain hardened by cold working
8 indicates full hardness
23
Q
Temper designations
H19
A
Strain hardened by cold working
9 indicates extra hard
24
Q
Temper designations
H2
A
Strain hardened by cold working and partially annealed
25
Temper designations
H3
Strain hardened and stabilized
26
Heat treatment
O
Annealed
27
Heat treatment
F
As fabricated
28
Heat treatment
T
Heat treatable alloy
29
Heat treatment
T3
Solution Heat treated and strain hardened
30
Heat treatment
T36
Solution Heat treated and strain hardened
6= amount strain hardening, reduction of 6%
31
Heat treatment
T4
Solution Heat treated and room temp aging
32
Heat treatment
T6
Solution Heat treated and artificial aging
33
Aluminum Alloying Elements
1xxx
Aluminum (99% pure)
34
Aluminum Alloying Elements
2xxx
Copper
35
Aluminum Alloying Elements
3xxx
Manganese
36
Aluminum Alloying Elements
4xxx
Silicon
37
Aluminum Alloying Elements
5xxx
Magnesium
38
Aluminum Alloying Elements
6xxx
Magnesium and silicon
39
Aluminum Alloying Elements
7xxx
Zinc
40
Aluminum Alloying Elements
8xxx
Other Elements
41
Identify AA 2024-T3
AA- Aluminum association
2- copper
0- no mods
24- 24th alloy in the family
T- heat treated
3- solution Heat treated and strain hardened
42
Solution Heat treatment
Heating of an alloy to a temperature at which a particular constituent will enter into solid solution followed by cooling at a rate fast enough to prevent the dissolved constituent from precipitating
43
Precipitation heat treatment
A treatment involving the heating or aging of an alloy at elevated temperature to cause a constituent to precipitate from solid solution. To separate
44
Purpose of heat treating
Used to alter physical/chemical properties of a material and achieve desired results such as hardening or softening.
45
Annealing
Heating to just above critical point, soaking in that temp then cooling slowly.
46
Natural aging
Cooling at room temp/air temp
47
An alloyed aluminum that has a thing pure aluminum layer mechanically attached that provides corrosion protection. Layer has a thickness of 5% total thickness on each side.
ALCLAD
48
How does the pure aluminum on ALCLAD prevent corrosion
Oxide layer forms on pure aluminum. Aluminum oxide is impervious (non-porous) to water, protects alloy. The alloy itself would not do this as the copper, zinc etc. would react with aluminum in presence of water.
49
Why is magnesium a useful alloy/metal for Aircraft materials?
Magnesium weighs two thirds that of aluminum. Hexagonal unit shaoe makes toughness a property.
50
Disadvantage of magnesium?
Burns/ignites, hard to extinguish.
51
Advantages of titanium
```
High strength to weight ratio
Resistant to stress cracking
Low coefficient thermal expansion
Resistant to most corrosive substances
Short term, extreme heat properties ideal for use in aircraft firewalls
```
52
Bright white Starbursts at end of stream would indicate which metal?
Titanium
53
Why is copper limited in its uses for structural material
Limited because of its weight.
54
This metal is used for spark plug gaskets due to its electrical conductivity
Copper
55
What is composed in bronze
Copper (75-90%) and tin( 10-25%)
56
What is composed in brass
Copper (55-70%) and zinc (30-45%)
57
What is brass commonly used for in aircraft?
Bearing metal and seal applications
58
Describe sintered metals and an advantage of sintered brass and bronze.
Sintering: objects created from metal powders held in molds, pressed then heated BELOW melting point.
Brass and bronze used as bushings that self lubricate due to oil retention of sintered form
59
Galling
Rubbing or mating of surfaces. Transfer of material between metallic surfaces via heat from motion. Metal gets hot it welds and the surface metal is destroyed.
60
Brinelling
Caused by excessive impact. Permanent indentation of hard surface
61
Spalling
Chipped away portion of hardened surface
62
Fretting
Corrosion due to vibration and slip in contact areas between materials
63
What are the 4 nickel alloys used in aviation?
Monel
K-Monel
Inconel
CRES (Corrosive Resistant Steel)
64
Monel
Nickel with 31.5% COPPER alloyed
Used in lockwire
High temp environment
65
K-Monel
Nickel alloy with small amount of aluminum
Preferred choice for landing gear components
Toughness and corrosive resistant
High fatigue strength
High UTS levels with proper hardening
66
Inconel
Nickel with 7.2% IRON and 15.8% CHROMIUM
| Lockwire
67
CRES (Corrosive Resistant Steel)
High iron content but included as nickel alloy
Austenitic CRES used for hardwire and lockwire
Fasteners prone to galling
68
Ferrous metals
Metals with iron in them (Fe)
69
How is iron ore reduce to iron metal?
What is the reduction process called?
Mixing ore with limestone and coke (pure carbon) and heating.
Carbon combines with oxygen forming superheated Co (carbon monoxide). Removes oxygen from iron ore.
Limestone melts and absorbs impurities from iron (flux)
Reduction process called SMELTING
70
What is pig iron
High carbon form of iron that is brittle and useless. Results after smelting.
71
How is steel made from pigs of iron?
Carbon is burned out of the metal then quantities of other elements are added into purified iron. Steel then poured into ingots.
72
SAE
Society Automotive Engineers
73
AISI
American Iron and Steel Institute
74
10xx-13xx are what type of steel groups?
Plain carbon steels
75
Identify
SAE 1020
SAE- Society Automotive Engineers
1- plain carbon steel
0- nothing added besides carbon
20- 20 points or 0.2% carbon added
76
Identify
SAE 1130
SAE- Society Automotive Engineers
1- plain carbon steel
1- Sulphur added, free machining steel
30 -30 points carbon 0.3%
77
Percentage of carbon in LOW carbon steels
0.10% to 0.30%
78
Percentage of carbon in MED carbon steels
0.30% to 0.50%
79
Percentage of carbon in HIGH carbon steels
0.50% to 1.05%
80
Steel alloys
1xxx
Plain carbon steel-low
81
Steel alloys
2xxx
Nickel
82
Steel alloys
3xxx
Nickel chromium
83
Steel alloys
4xxx
Molybdenum
84
Steel alloys
5xxx
Chromium
85
Steel alloys
6xxx
Chromium vanadium
86
Steel alloys
8xxx
Nickel, chromium, molybdenum
87
Steel alloys
11xx
Sulfur mod
88
Steel alloys
12xx
Sulfur and phosphorus mod
89
Steel alloys
13xx
Sulfur, phosphorus and manganese mod
90
Identify
SAE 2330
SAE- Society Automotive Engineers
2-nickel major alloy element
3- approx percentage of nickel
30- carbon points 0.3%
91
In 4130, what does the "1" stand for
4= Molybdenum family
| 1=Percentage of chromium
92
Hardness
Ability of metal to resist abrasion, penetration, permanent distortion
93
When quenching what should you do when submerging metal in substance?
Agitate it, so you reduce boundary layer from insulating and resulting uneven temperatures
94
Quenching
Results change in microstructure, gives tool high hardness and brittleness
95
Purpose of tempering
Trade brittleness for plasticity
96
Normalizing
Carried out by heating to above critical temperature then cooled at room temperature
97
Casehardening
Hardness process where the outer shell of metal goes through a chemical reaction to harden and become stronger around the core.
98
Carburizing
Carbon used as hardening agent in casehardening
99
Nitriding
Raising temperature to 900⁰-1150⁰ F then introducing ammonia gas (NH3) Gas decomposes into nitrogen gas.
Nitrogen infuses and reacts with elements in metal to form nitrites which harden the surface. Creates a 0.060 layer. Copper used on areas not to be nitrided
100
Babbit
Mixture of soft metals (lead, aluminum, copper) with metals (zinc, cadmium) resulting a metal alloy capable of long life. Used as bearings due to resistance of galling.
101
_____ is the #1 issue in aircraft design
Weight
102
Why are aircraft structures easily damaged?
Because they are lightweight
103
Primary structure
Portion of an airplane that would seriously endanger its safety if it failed.
104
Examples of primary structures
Wing spars, wing, fuselage skins, control surfaces, engine mounts
105
Secondary structures
Structure not critical to flight and ground safety.
106
Examples of secondary structures
Cowlings, fairings, interior furnishing, unpressurized windows, stringers
107
What type of fuselage construction is this
Truss
108
Longitudinal members that extend across several frame members and help the skin support primary bending loads.
Longerons
109
____relies on triangles to make it strong
Truss
110
A ___truss uses mostly diagonal bracing
Warren
111
A ____truss uses perpendicular bracing
Pratt
112
Gusset
Plate used to strengthen joint in a structure
113
This type of construction is extruded as one piece which makes it stronger than welded portions. It does not have longerons or stringers and the outer skin carries the primary loads
Monocoque (single shell)
114
Former
A structure that gives shape to the fueslage much like a rib would in a wing
115
Bulkhead
A structure that gives shape to the fuselage, a "face" to a sub-structure
116
What kind of construction type is this
Semi-monocoque
117
Short pieces between longerons. Provide shape and attachment for skin
Stringers
118
Extend over several formers helping skin support primary bending loads
Longerons
119
Advantages of semi-monocoque
Additional internal structure helps lighten weight as skin can be thinner. Design choice for pressurized cabins
120
Full cantilever
121
Semi-cantilever
122
What are the small structures attached to the struts called
Jury struts
123
Identify parts of wing construction
124
When you tighten drag wires, why are you able to tighten both ends
There are right hand and left hand threads on each end
125
Primary load carrying component in a wing, horizontal stabilizer, vertical stabilizer, most control surfaces etc.
Spar
126
If height is doubled in a Spar....
Carry ability is quadrupled
127
Secondary structure component in a wing. Gives aerodynamic shape, holds spars upright, gives rigidity, transfers loads
Ribs
128
In combination with spars and ribs, what is designed to carry part of flight and ground loads?
Wing skin
129
What is a wet wing
Wing that carries fuel, sealed with fuel resistant sealant.
130
Smooth airflow, non-load carrying, tertiary structure. Reduces interference drag
Wing root fairings
131
This landing gear is located between nose wheel and main wheels
Tricycle
132
This landing gear has a wheel at the tail end
Conventional
133
Methods of checking relative alignment of an aircraft
Special dihedral board with spirit level
| Incidence board
134
Symmetry check on small aircraft
Measurements between points taken with steel tape
135
Symmetry check on large aircraft
Spring scale to obtain equal tension. Dimension position chalked on floor using plumb bobs.
Can also use a construction transit
136
What is the primary objective of aircraft repair?
To restore damaged parts to original condition.
137
What do you look for in the case of damage from a lightning strike?
Bearing damage, melted resin in composites
138
What's the main thing to look for to identify a hard landing?
Wrinkling skin
139
How do you check a float for leaks
Put plane in after for 24 hours or fill float.
140
Should you use blind rivets on floats?
No, they create leaks
141
A location where cross-sectional area of a part changes abruptly
Stress riser
142
What must you do after repainting an aircraft control surface. And why?
Rebalance it as the weight may have changed from the paint and could cause flutter.
143
True or false.
| Any time a repair is made to an aircraft, the same material (alloy) must be used
True
144
As an AME basic knowledge of aircraft materials is used to:
Correct choice of material for repair
Correct choice of surface treatments needed for corrosion
Understand load levels of fasteners
145
3 classes to describe material properties and their descriptions
Mechanical, how a material acts/works (torsion)
physical, how a material described (balsa wood, Sitka spruce)
chemical, how a material reacts with other materials
146
Examples of mechanical properties
```
Plasticity
Ductility
Malleability
Brittleness
Elasticity
Strength
Fatigue
Creep
```
147
Examples of physical properties
```
Electrical/conductivity
Thermal conductivity
Magnetic conductivity
Melting point
Specific gravity
Density
Colour
Thermal coefficient
```
148
Examples of chemical properties
Oxidization
Reduction
Corrosion
149
Phenomenon of progressive failure of a material due to cyclical induced cracking
Fatigue
150
If we prevent tension loading on the surface ____can be prevented if not postponed
Fatigue failure
151
A process that puts compressive load on the surface to counter tension loads which normally break a part. Done with metal balls, accurately shot at surface until smooth.
Shot peening
152
Metal fatigue cracks can only start where metal is in ____ not ____
Tension, not compression
153
Slow plastic deformation, change in geometry when parts subjected to load. Caused by load valued below materials yield point over time
Creep
154
How do you check for blade creep
Use a feeler gauge to measure thickness between blade and encasing ring
155
Temperature which material will change from solid to liquid
Melting point
156
Comparison of weight of given volume with equal volume of demineralized water.
Specific gravity
157
Weight per unit volume of a material
Density
158
Ability of material to reflect and absorb different wavelengths of light energy
Colour
159
The change in the physical dimension of a material due to its level of thermal energy
Thermal coefficient of expansion
160
Two metals bonded with different coefficients of expansion.
Bimetal strip
161
Combination of an element with oxygen to form an oxide. Result physical, chemical and mechanical properties differ drastically from the original element properties
Oxidation
162
Removal of oxygen from a compound or oxide to isolate element
Reduction
163
Undesirable attack on a material. May take form of atmospheric, submarine, subterranean or electrolytic attack.
Corrosion
164
Derives it's scale numbers from the DEPTH of the imprint it makes in the metal. Uses diamond cone
Rockwell
165
Diagonal measurement of hardness testing. Measure impression diagonals
Vickers
166
Hardness number derived from DIAMETER of indentation in test piece. Use microscope
Brinell
167
Derived by depth of indentation. Used for soft metals.
Barcol
168
Ability of material to resist tearing under bending or tensile loads
Toughness
169
Materials resistance that opposes deformation due to applied external load. Measured in kpi
Stress
170
The degree of deformation due to stress
Strain
171
Testing materials to their failure point to find their ultimate strength
Destructive testing
172
Point where permanent deformation takes place. Plastic
Yield point
173
Point just prior to failure
Ultimate tensile strength
174
What region precedes the yield point
Elastic region
175
Columns of stacked cells
Cellulose Fibre
176
Complex of thermoplastic matrix which holds the fibers in position.
Lignin
177
The living rings of cells between the heartwood and outside of the tree (bark)
Sapwood
178
The dormant rings of cells starting with the pith and radiating out. Preferred lumber source
Heartwood
179
The very center column of cells, the first growth of the tree
Pith
180
Growth layer. The cell manufacturing layer between the sapwood and the bark
Cambium
181
The covering of the tree which provides the tree with protection. Dead and dry
Bark
182
The large cell concentration produced in cooler wetter conditions
Springwood
183
Smaller more dense cell concentration produced during warmer, drier conditions
Summerwood
184
This wood comes from deciduous trees. Angiosperms (seeds have coverings like fruit)
Hardwood
185
This wood comes from coniferous (cone-bearing) trees. Gymnosperms (no seed covering)
Softwood
186
The standard wood for all wood used in aircraft structures.
Sitka spruce
187
Method of sawing dimensional lumber from a log to produce a board with the growth rings perpendicular to the face of the board. Results most stable, highest quality lumber being produced
Quarter sawing
188
Quarter sawn exhibits ____grain
Vertical
189
Plain or flitch sawn lumber exhibits ____grain
Angular or flat
190
Refers to alternating regions of darker and lighter wood resulting from the differing growth parameters in different seasons
Grain
191
This shrinkage occurs perpendicular to growth lines
Lineal shrinkage
192
Shrinkage occurs parallel to growth rings
Tangential
193
What shrinkage is the largest dimension of shrinkage that often causes checking
Tangential
194
A form of wood, one piece
Solid
195
A form of wood, more than one piece with grain running the same direction
Laminated
196
Form of wood, more than one piece with grain running different directions
Plywood
197
Max grain deviation
1:15 rise over run
198
Ac43.13 lists minimum and naxinum ring count for Aircraft wood at ______rings per inch
6 and 15
199
What ring count is preferred according to ac43.13
12-15
200
When viewed from end, a board face edge will have an angle between it and growth rings, between ______
45-90⁰, 45 is minimum. 90 is ideal
201
A portion of a branch that is embedded in wood of a tree trunk
Knot
202
When two growth rings separate along their circumferential surfaces, a sticky solution fills the gaps
Pitch pocket
203
Environmental imbalance causes tree to compensate by growing dense wood on one side of trunk. A pith is offset from center. Excess of summerwood. Too brittle for use.
Compression wood
204
Natural result of bound water reduction in logs from saturated state to required equilibrium water content less than 15% of the weight. Not permitted in certified wood
Checks
205
A moisture content of ____ in wood is approved. ___is preferred
8-15%, 10-12% preferred
206
Separation of cells in any direction from mechanical force. Can be caused by a check in drying process
Splits
207
What are indications of decay
Softening, swelling, discolored, bad odor
208
How do you check wood for decay
Pick at it with knife, chunks out means rot. Can also check for hollow sound with tap test.
209
What must wood be protected with
Quality marine varnish (2 part epoxy)
210
Plasticized lacquer that is applied to fabric covered aircraft. Tightens and stiffens.
Dope
211
The gold standard glue used in wood repairs
Resorcinol formaldehyde synthetic resin glue
212
Obsolete glue used in aviation due to short life in hot moist conditions
Urea formaldehyde resin glue
213
Sometimes reduced in hot moist environments
Epoxy resin araldite
214
Plastic that can be reheated and reformed. Ex: Lignin
Thermoplastic Resin
215
Plastic that once set, cannot be reheated and reformed. Ex: Epoxy
Thermosetting Plastic Resin
216
Unique low frictional coefficient, high toughness, electrical insulation, resists heat, high impact strength, gear used to drive distribution wiper in aircraft magneto
Nylon
217
Thermoplastic resin with nylon slipperiness. Proper name is polytetrafluoroethylene. Toughness of this and low friction coefficient makes it a good bearing material. No lubrication needed due to low friction
Teflon
218
Disadvantages of polyester resin
High cure shrink, limited working time, moderate mechanical properties,
219
2 part adhesive that gives off heat due to chemical reaction. Exothermic reaction.
Epoxy
220
This can be a brittle substance of a 2 part adhesive used to paint aircraft. Adding softeners can make it not chip at all
Epoxy paint
221
What is an example of a phenol formaldehyde resin or phenolic.
Micarta, bakelite, formica
222
Reinforcing fiber that is added to phenolic too give toughness
Flox
223
Examples of flox used in phenolic formaldehyde resins
Linen, cotton, glass, nylon , paper
224
____ agents used to thicken and reinforce thermosetting plastic resins.
Thixotropic
225
Examples of thixotropic additives
Microbaloons,
226
A chemical process for converting rubber or related polymers into more durable materials via addition of Sulfur or other relevant curative or accelerators
Vulcanization
227
Aviation sealants are 2 parts mixed by __
Weight
228
Organic natural sources of covering fabric
Cotton, linen and silk
229
Synthetic sources of fabric covering
Polyester, glass, nylon
230
Grade A cotton must have a min tensile strength of ___per inch
80lbs
231
How can you test integrity of fabric
With seyboth or Maule test
232
Service strength of fabric must be __ of original
70%
233
Process of dipping fabric into caustic soda then rolling in a calendar mill to increase strength, Lustre and lay out knap (little stray fibers)
Mercerizing
234
More threads, one direction
Uni-directional
235
Same number of threads in both directions
Bi-directional
236
Where is the warp of the fabric located?
Along the salvage edge, running down the roll
237
Where is the fill located
Across the fabric, from salvage edge to salvage edge.
238
Used originally on cotton, highly flammable, cotton fibers dissolved with nitric acid along with other additives.
Nitrate dope
239
Developed by the US Navy, cellulose fibers dissolved in acetic said and butyric acid plus additives. Less adhesive, less flammable
Butyrate dope
240
Why is butyrate dope added on top of nitrate dope?
Nitrate dope is more adhesive and will stick to fabric better. Butyrate sticks better directly to nitrate dope
241
What is added to dope to protect from UV rays
Aluminum powder
242
Glass resistant to electricity, good resistance to fatigue, high strength, 98% of fibers borosilicate glass.
E-Glass
243
Structural glass, lighter and stronger than E-glass,
S-Glass
244
This material is made from nylon, impact resistant "bulletproof", high tensile strength, low compressive strength, not used on critical structures, absorbs water, requires special tools to cut
Aramid Fibers (Kevlar)
245
This material is high tensile strength, lightweight, black in colour, fails without warning when stress limit is reached, negative coefficient of thermal expansion, causes issues with thermal balance
Carbon fiber
246
This material is very stiff and has Hugh tensile and compressive strength. Usually prepreg, large diameter makes it hard to bond to curved surfaces, used to repair aluminum, barbed molecules hazardous to health
Boron fibers
247
The performance of a composite structure depends on what.
The orientation of the fibers
248
What are some honeycomb core materials?
Paper, nomex, carbon, fiberglass, metal,
249
How do you inspect for delamination
Tap test, soft/desd sound indicates delamination
250
Impact damaged honeycomb is repaired with a ____or ____ type repair
Scarf or patch
251
Heat sources used for composite repair
Oven, autoclave, heat blanket, heat lamp, hot air systems.
252
Corrosion resistant steel most often used in aviation?
18-8 (chromium and nickel)
253
What is quasi-isotropic layup
Multiple layers of materials all differing by 45 degrees in orientation
254
Three designs of wing construction?
Monospar, multispart and box beam
255
Carbon fiber advantages
High strength, corrosion resistance
256
Tempering always follows ____ never precedes
Hardening
257
What's the difference between carbon and graphite planes?
Graphite is 3d, carbon is 2d
258
Types of wooden ribs?
Plywood web, lightened plywood web, truss types
259
Max years fabric can be in service
15-20 years
260
What does magnesium silicon allow in an alloy?
Makes alloy heat treatable
261
What does the first digit in the wrought aluminum designation indicate?
Identifies the alloy type
262
Main types of aircraft structures?
Truss and monocoque
263
Firewalls can be made of what steel?
Stainless steel
264
How do you cut dry prepreg fabric?
With a special knife
265
What does Sulfur do when added to metal?
Improves machinability
266
Aluminum alloy mostly used for fuel tanks?
5052, 3003
267
Purpose of stringers?
Give shape, attach skin, prevent tension and compression from bending fuselage
268
Aluminum alloys commonly hardened by?
Cold working
