Engineering Materials Flashcards: Plastics, Metals and Processing
96 English cards on material properties, metal and polymer families, manufacturing processes, and qualified selection cases, including sourced ABS and PA6 grades.
Mayelana naleli qoqo
Learn engineering materials through concise retrieval and constrained selection problems. These 96 original English cards connect property vocabulary, metal and polymer families, processing mechanisms and practical evidence checks.
Practise concept-to-explanation recall, selected situation-to-property or process choices, alloy-family recognition, and named-grade interpretation for ABS (INEOS Terluran GP-22) and PA6 (BASF Ultramid B3S and B3EG6). A suggested material or process is a screening candidate, not a qualified design.
The sequence introduces properties, then metals, polymers and manufacturing processes. Each topic progresses from mechanisms to applications. Selected case variants are separated from their foundation cards; the review scheduler handles later spacing.
Excluded: automatic reverse cards for every definition, generic numerical property rankings, machine settings, full phase diagrams and design allowables. Exact material properties require the correct grade, test method, temperature, moisture state, orientation and processing history. This is an evergreen topic deck, not a complete materials course or exam syllabus.
AI-assisted questions, answers and generated cover were independently composed and checked against technical sources. No private learner cards, textbook exercises, exam questions or third-party images were copied. Original wording, organization and generated media are offered under CC0 1.0 to the extent applicable rights exist; facts and third-party source material retain their own status.
Factual references include INEOS Terluran GP-22, BASF Ultramid, University of Illinois materials principles, Instron materials testing terms, TWI injection moulding and American Foundry Society metalcasting.
Independent educational material; no affiliation with or endorsement by the named manufacturers, technical bodies or universities.
Amakhadi akuleli qoqo
Ikhadi 1
Umbuzo
Engineering stress in a tensile test: force divided by what?
Impendulo
Original specimen cross-sectional area.
Ikhadi 2
Umbuzo
Engineering strain in a tensile test: extension divided by what?
Impendulo
Original gauge length. Strain is dimensionless.
Ikhadi 3
Umbuzo
Elastic deformation: what happens after unloading?
Impendulo
The deformation recovers.
Ikhadi 4
Umbuzo
Young’s modulus describes which material behaviour?
Impendulo
Resistance to elastic tensile or compressive strain, in the linear elastic region.
Ikhadi 5
Umbuzo
Yield strength marks the onset of what?
Impendulo
Significant permanent deformation, using the specified yield or proof criterion.
Ikhadi 6
Umbuzo
Ultimate tensile strength: which point on an engineering stress–strain curve?
Impendulo
The maximum engineering tensile stress.
Ikhadi 7
Umbuzo
Ductility describes what happens before tensile fracture?
Impendulo
How much plastic deformation the material can undergo.
Ikhadi 8
Umbuzo
Indentation hardness measures resistance to what?
Impendulo
Localized permanent penetration by an indenter.
Ikhadi 9
Umbuzo
Tensile toughness: what does the area under the stress–strain curve to fracture represent?
Impendulo
Energy absorbed per unit volume up to fracture under those test conditions.
Ikhadi 10
Umbuzo
Density relates which two quantities?
Impendulo
Mass per unit volume.
Ikhadi 11
Umbuzo
Thermal conductivity describes which ability?
Impendulo
Transferring heat through a material under a temperature gradient.
Ikhadi 12
Umbuzo
Electrical conductivity describes which ability?
Impendulo
Carrying electric current under an electric field.
Ikhadi 13
Umbuzo
Creep: what changes under a sustained load over time?
Impendulo
Deformation increases with time; temperature and stress affect the rate.
Ikhadi 14
Umbuzo
Fatigue damage is associated with what loading pattern?
Impendulo
Repeated or fluctuating loading that can initiate and grow cracks.
Ikhadi 15
Umbuzo
Brittle fracture: how much plastic deformation precedes it?
Impendulo
Little plastic deformation compared with ductile fracture under the same test conditions.
Ikhadi 16
Umbuzo
A bracket bends too far but recovers fully. Which property should you examine first?
Impendulo
Elastic stiffness: material modulus together with the bracket’s geometry.
Ikhadi 17
Umbuzo
A metal clip stays bent after one overload. Which threshold was exceeded locally?
Impendulo
Its yield threshold; permanent deformation occurred.
Ikhadi 18
Umbuzo
A housing must absorb a drop without fracture. Which evidence matters beyond tensile strength?
Impendulo
Impact-test performance under relevant temperature, notch and geometry conditions.
Ikhadi 19
Umbuzo
Two materials have equal yield strength. Must their tensile toughness be equal?
Impendulo
No. Different ductility can produce different energy absorption before fracture.
Ikhadi 20
Umbuzo
A plastic clamp slowly loosens at fixed deflection. Which time-dependent effect is this?
Impendulo
Stress relaxation: the stress decreases while the imposed deformation is held.
Ikhadi 21
Umbuzo
Does a higher hardness alone prove a part will resist every wear mechanism?
Impendulo
No. Wear also depends on contact, loading, lubrication and the wear mechanism.
Ikhadi 22
Umbuzo
Why compare impact results only with matching test conditions?
Impendulo
Specimen geometry, notches, temperature and test method affect measured impact behaviour.
Ikhadi 23
Umbuzo
Can a generic family property range serve as a finished-part design allowable?
Impendulo
No. Select a grade, condition and relevant design data before qualifying the part.
Ikhadi 24
Umbuzo
A lighter material is proposed for the same-size part. Which property predicts its mass change?
Impendulo
Density, provided the volume remains the same.
Ikhadi 25
Umbuzo
Ferrous versus nonferrous metals: what is the defining distinction?
Impendulo
Whether iron is the main constituent. Nonferrous does not mean completely iron-free.
Ikhadi 26
Umbuzo
Steel belongs to which basic alloy family?
Impendulo
Iron-based alloys containing carbon, often with other alloying elements.
Ikhadi 27
Umbuzo
Why specify a steel grade and heat treatment rather than just “steel”?
Impendulo
Composition and processing change its microstructure and mechanical properties.
Ikhadi 28
Umbuzo
What is a grain in a polycrystalline metal?
Impendulo
A crystalline region with a particular lattice orientation.
Ikhadi 29
Umbuzo
What separates neighbouring metal grains with different orientations?
Impendulo
A grain boundary.
Ikhadi 30
Umbuzo
Which crystal defect commonly moves during plastic deformation of metals?
Impendulo
A dislocation.
Ikhadi 31
Umbuzo
Cold working usually trades increased strength for what?
Impendulo
Reduced ductility, as plastic deformation impedes further dislocation motion.
Ikhadi 32
Umbuzo
What is a common purpose of annealing a cold-worked metal?
Impendulo
Restore ductility and reduce hardness through a controlled heat treatment.
Ikhadi 33
Umbuzo
Quenching in metal heat treatment means what cooling step?
Impendulo
Rapid cooling using a specified medium; the appropriate regime depends on the alloy and intended result.
Ikhadi 34
Umbuzo
What gives stainless steel much of its corrosion resistance?
Impendulo
A thin chromium-rich passive surface film.
Ikhadi 35
Umbuzo
Why distinguish grey cast iron from ductile cast iron during selection?
Impendulo
Graphite form and resulting mechanical behaviour differ; “cast iron” is not one property set.
Ikhadi 36
Umbuzo
Why are aluminium alloys often screened for lightweight structures?
Impendulo
Their relatively low density can help reduce mass; stiffness, strength and geometry still need checking.
Ikhadi 37
Umbuzo
Why is copper often screened for electrical conductors?
Impendulo
High electrical conductivity; cost, strength and connection design also matter.
Ikhadi 38
Umbuzo
Brass is principally an alloy of copper with which element?
Impendulo
Zinc.
Ikhadi 39
Umbuzo
Traditional tin bronze is principally an alloy of which two elements?
Impendulo
Copper and tin. Other bronze families use different alloying additions.
Ikhadi 40
Umbuzo
Does “stainless” mean immune to chloride corrosion?
Impendulo
No. Grade, environment and surface condition still govern corrosion resistance.
Ikhadi 41
Umbuzo
Two dissimilar metals touch in salty water. Which corrosion mechanism should be checked?
Impendulo
Galvanic corrosion, because electrical contact and an electrolyte can form a galvanic couple.
Ikhadi 42
Umbuzo
Can you rank aluminium and steel parts by stiffness using only their material names?
Impendulo
No. Compare the actual moduli and part geometries for the required loading.
Ikhadi 43
Umbuzo
A copper alloy is stronger than pure copper. Must it conduct electricity equally well?
Impendulo
No. Alloying changes conductivity as well as mechanical properties; check that alloy’s data.
Ikhadi 44
Umbuzo
A steel sheet cracks during forming after extensive cold work. What processing step may restore formability?
Impendulo
An appropriate anneal before further forming; confirm the alloy-specific procedure.
Ikhadi 45
Umbuzo
What is a common purpose of tempering a quench-hardened steel?
Impendulo
Improve toughness and ductility, usually with some reduction in hardness.
Ikhadi 46
Umbuzo
How can an insulating washer help a dissimilar-metal joint resist galvanic corrosion?
Impendulo
By interrupting the electrical connection, if the whole joint is electrically isolated.
Ikhadi 47
Umbuzo
Before approving a welded metal component, which material region besides the weld metal needs consideration?
Impendulo
The heat-affected zone, whose thermal cycle can change properties without melting it.
Ikhadi 48
Umbuzo
What is the key processing–structure–property lesson for metal selection?
Impendulo
A chemical composition alone does not determine performance; processing changes microstructure.
Ikhadi 49
Umbuzo
A polymer is built from what kind of molecular structure?
Impendulo
Large molecules containing many linked repeating units.
Ikhadi 50
Umbuzo
Which polymer class can usually be reheated and reshaped: thermoplastics or cured thermosets?
Impendulo
Thermoplastics. Cross-links in a cured thermoset prevent ordinary melt reshaping.
Ikhadi 51
Umbuzo
What deformation behaviour distinguishes an elastomer?
Impendulo
It can undergo substantial deformation and recover toward its original shape when the load is removed, within its working range.
Ikhadi 52
Umbuzo
What does “semi-crystalline polymer” mean?
Impendulo
Ordered crystalline regions coexist with amorphous regions.
Ikhadi 53
Umbuzo
Which polymer regions undergo glass transition: amorphous or crystalline?
Impendulo
Amorphous regions. Around the glass transition, motion of chain segments becomes much easier.
Ikhadi 54
Umbuzo
What structural feature prevents a cured thermoset from flowing like a thermoplastic melt?
Impendulo
A covalently cross-linked network.
Ikhadi 55
Umbuzo
Why are plasticizers added to some polymer formulations?
Impendulo
To increase flexibility; the amount and compatibility affect the final properties.
Ikhadi 56
Umbuzo
Why add UV stabilizers to a polymer intended for outdoor exposure?
Impendulo
To reduce degradation caused by ultraviolet exposure; the formulation and exposure still need verification.
Ikhadi 57
Umbuzo
Why can adding glass fibres make moulded polymer properties direction-dependent?
Impendulo
Fibres become oriented during flow, so reinforcement differs with direction.
Ikhadi 58
Umbuzo
What structural change separates glass transition from crystalline melting in a polymer?
Impendulo
Glass transition increases chain-segment mobility in amorphous regions; melting breaks down the ordered crystalline regions.
Ikhadi 59
Umbuzo
ABS is an abbreviation for which polymer name?
Impendulo
Acrylonitrile butadiene styrene.
Ikhadi 60
Umbuzo
PA6 is another name for which polyamide?
Impendulo
Polyamide 6, also called nylon 6.
Ikhadi 61
Umbuzo
Why distinguish “dry” from “conditioned” polyamide property data?
Impendulo
Moisture conditioning changes the material state and can change mechanical behaviour.
Ikhadi 62
Umbuzo
Does one grade’s ABS datasheet establish the properties of every ABS grade?
Impendulo
No. Formulation, grade, test method and conditions must match the claim.
Ikhadi 63
Umbuzo
INEOS Terluran GP-22 is specified for which main shaping process?
Impendulo
Injection moulding; it is a general-purpose ABS grade.
Ikhadi 64
Umbuzo
BASF Ultramid B3S is supplied for which main shaping process?
Impendulo
Injection moulding; BASF describes this PA6 grade as easy-flowing and finely crystalline.
Ikhadi 65
Umbuzo
A warm polymer bracket carries a constant load for months. Which data are needed beyond a short tensile test?
Impendulo
Long-term creep data for the relevant load, temperature and material condition.
Ikhadi 66
Umbuzo
Ultramid B3EG6 differs from unreinforced PA6 by which reinforcement?
Impendulo
BASF specifies glass-fibre reinforcement for this PA6 injection-moulding grade.
Ikhadi 67
Umbuzo
Which part category does INEOS identify as a particular application for Terluran GP-22?
Impendulo
Housings, including appliance housings. This is a candidate application, not automatic design approval.
Ikhadi 68
Umbuzo
Why keep opened Ultramid B3S granule containers carefully closed?
Impendulo
To limit moisture absorption before processing.
Ikhadi 69
Umbuzo
Can glass-filled PA6 data replace unfilled PA6 data in a design check?
Impendulo
No. Reinforcement changes the material; use the exact grade and relevant orientation data.
Ikhadi 70
Umbuzo
Must a thermoplastic part be accepted by the local recycling system?
Impendulo
No. Remeltability alone does not establish collection, sorting or recycling compatibility.
Ikhadi 71
Umbuzo
For an outdoor ABS housing, is a good indoor impact result enough evidence?
Impendulo
No. Check weathering, temperature and the exact grade’s suitability for the exposure.
Ikhadi 72
Umbuzo
BASF lists grips and fixing clamps for Ultramid B3S. What remains to verify for a loaded clamp?
Impendulo
Grade-specific long-term behaviour at the actual temperature and moisture state, plus the part geometry.
Ikhadi 73
Umbuzo
Metal casting shapes a part by which change of state?
Impendulo
Liquid metal solidifies inside a mould.
Ikhadi 74
Umbuzo
Forging shapes metal by what basic mechanism?
Impendulo
Compressive plastic deformation of solid metal; it may be performed hot or cold.
Ikhadi 75
Umbuzo
Extrusion is particularly suited to which basic geometry?
Impendulo
A continuous length with a substantially constant cross-section, formed through a die.
Ikhadi 76
Umbuzo
CNC machining is additive or subtractive?
Impendulo
Subtractive: controlled cutting removes material from a workpiece.
Ikhadi 77
Umbuzo
Injection moulding of a thermoplastic: what happens after the cavity fills?
Impendulo
The melt cools and solidifies before the part is ejected.
Ikhadi 78
Umbuzo
Thermoforming starts from which form of plastic stock?
Impendulo
A sheet heated until formable, then shaped over or into a mould.
Ikhadi 79
Umbuzo
Blow moulding is commonly used for which type of plastic part?
Impendulo
Hollow parts, such as bottles, formed by inflating a heated preform or tube in a mould.
Ikhadi 80
Umbuzo
Additive manufacturing builds geometry by what basic approach?
Impendulo
Adding material, commonly layer by layer, from a digital model.
Ikhadi 81
Umbuzo
In milling, what typically rotates to remove material?
Impendulo
The cutting tool.
Ikhadi 82
Umbuzo
Why may a cast part still need machining?
Impendulo
Selected surfaces may need tighter tolerances or a better finish than the casting provides.
Ikhadi 83
Umbuzo
Sand casting and permanent-mould casting mainly differ in what tooling feature?
Impendulo
Sand moulds are expendable; permanent moulds are reused.
Ikhadi 84
Umbuzo
Why can injection moulding be costly for a very small production run?
Impendulo
Tooling cost is spread across too few parts; compare total cost at the required volume.
Ikhadi 85
Umbuzo
A long plastic tube has the same cross-section throughout. Which process is a natural first candidate?
Impendulo
Extrusion, followed by cooling and cutting to length.
Ikhadi 86
Umbuzo
A thin plastic packaging tray must be formed from sheet. Which process is a natural first candidate?
Impendulo
Thermoforming; check wall thinning and the required detail.
Ikhadi 87
Umbuzo
Why should a forged part’s grain flow be considered in design?
Impendulo
Deformation creates directional structure; the load direction and process route affect performance.
Ikhadi 88
Umbuzo
A design needs a few changing metal prototypes. Why consider CNC machining before buying a production mould?
Impendulo
It can make revised parts directly from stock without dedicated mould tooling.
Ikhadi 89
Umbuzo
What distinguishes a fusion-weld heat-affected zone from the fusion zone?
Impendulo
The heat-affected zone changes thermally but does not melt; the fusion zone melts and resolidifies.
Ikhadi 90
Umbuzo
Why clean and prepare a metal surface before applying a protective coating?
Impendulo
Contaminants and surface defects can impair coating adhesion and performance.
Ikhadi 91
Umbuzo
Does a corrosion-resistant coating make the underlying material irrelevant?
Impendulo
No. Damage, adhesion, exposure and substrate compatibility still matter.
Ikhadi 92
Umbuzo
Why check build orientation when selecting a layer-built polymer part?
Impendulo
Layer bonding and deposition can make strength depend on direction.
Ikhadi 93
Umbuzo
A hollow plastic bottle needs a shaped enclosed body. Which process family should you screen first?
Impendulo
Blow moulding; select the exact variant for the material and geometry.
Ikhadi 94
Umbuzo
Many identical thermoplastic housings are needed. Which process deserves early cost comparison?
Impendulo
Injection moulding, because repeat production can spread tooling cost over many parts.
Ikhadi 95
Umbuzo
Why does choosing a process also affect material selection?
Impendulo
Materials must tolerate that process and achieve the required finished-part properties.
Ikhadi 96
Umbuzo
Before releasing a selected material–process combination, what evidence closes the selection loop?
Impendulo
Verify the exact grade, processing condition and part performance against the actual requirements.
amakhadi angu-96
Engineering Materials Flashcards: Plastics, Metals and Processing
I-Nibomo iyavuleka ukuze uqale ukufunda.