Engineering Materials and Metallurgy MCQs 2026

Titanium alloys advantage is

1. A high strength-to-weight ratio and corrosion resistance ✓
2. B lowest melting point of all metals ✓
3. C always cheaper than mild steel ✓
4. D cannot be welded ever ✓

Composite materials combine

1. A only single pure element always ✓
2. B matrix and reinforcement for tailored properties ✓
3. C only water and oil ✓
4. D only one grain boundary ✓

Fiber direction in composites primarily controls

1. A isotropic behaviour in all directions always ✓
2. B only colour ✓
3. C anisotropic strength and stiffness ✓
4. D only density reduction only ✓

Glass transition temperature Tg of polymer is

1. A melting of iron carbide ✓
2. B boiling of water ✓
3. C temperature where amorphous polymer becomes rubbery on heating ✓
4. D Curie point of nickel only ✓

Thermoplastics can be

1. A only cured irreversibly like thermosets always ✓
2. B re-melted and reshaped repeatedly ✓
3. C only used as liquids always ✓
4. D never injection moulded ✓

Thermosetting plastics once cured

1. A soften reversibly like wax always ✓
2. B become metals ✓
3. C cannot be re-melted without degradation ✓
4. D evaporate instantly ✓

Inoculation in cast iron promotes

1. A only cementite formation always ✓
2. B only gas porosity ✓
3. C only martensite in cast iron ✓
4. D graphite nucleation for desired graphite form ✓

Segregation in castings causes

1. A perfect homogeneity always ✓
2. B only surface polish ✓
3. C only magnetic alignment ✓
4. D non-uniform composition and properties ✓

Hot shortness in metals is cracking during hot work due to

1. A low-melting grain boundary films (e.g. copper in steel) ✓
2. B only cold temperature ✓
3. C only high hardness ✓
4. D only magnetic fields ✓

Cold shortness is associated with

1. A only high temperature forging ✓
2. B excess phosphorus making steel brittle at low temperature ✓
3. C only austenite stability ✓
4. D only copper plating ✓

Recrystallization temperature for metals is approximately

1. A 0.3 to 0.5 times absolute melting temperature ✓
2. B twice melting point ✓
3. C room temperature always for steel ✓
4. D zero kelvin ✓

Allotropy of iron means

1. A iron never changes structure ✓
2. B iron exists in different crystal structures (BCC and FCC) at different temperatures ✓
3. C iron is only liquid at room temperature ✓
4. D iron has no carbon solubility ✓

Curie temperature of iron is about

1. A 770°C where ferromagnetism is lost ✓
2. B 27°C ✓
3. C 1538°C melting point ✓
4. D 1147°C eutectic ✓

Zinc coating on steel sheet is called

1. A tinning only always ✓
2. B anodizing ✓
3. C galvanizing ✓
4. D chromating only on aluminium ✓

Passivation of stainless steel uses

1. A nitric or citric acid treatment to strengthen oxide film ✓
2. B molten zinc dip only ✓
3. C carburizing gas ✓
4. D sand blasting only ✓

Pearlite lamella spacing affects

1. A only electrical resistivity of copper wire ✓
2. B strength and hardness with finer spacing giving higher strength ✓
3. C only paint viscosity ✓
4. D only air density at altitude ✓

Bronze traditionally is alloy of

1. A copper and tin ✓
2. B copper and zinc ✓
3. C iron and nickel ✓
4. D lead and tin only ✓

Stress corrosion cracking needs

1. A only compression in dry nitrogen ✓
2. B only cyclic impact in vacuum ✓
3. C only annealing temperature ✓
4. D tensile stress, susceptible alloy and corrosive medium together ✓

Powder metallurgy process sequence is typically

1. A casting, forging, welding only ✓
2. B only electroplating ✓
3. C only extrusion of billet ✓
4. D powder production, compaction, sintering ✓

Sintering temperature in PM is

1. A always above liquidus ✓
2. B at room temperature only ✓
3. C below melting point of main constituent ✓
4. D above boiling point ✓

Phase diagram horizontal line indicates

1. A variable composition single phase only ✓
2. B impossible equilibrium ✓
3. C only mechanical mixing ✓
4. D invariant reaction (eutectic, eutectoid or peritectic) ✓

Lever rule on phase diagram calculates

1. A hardness from cooling rate ✓
2. B mass fractions of two phases in two-phase region ✓
3. C electrical conductivity only ✓
4. D surface tension only ✓

Solid solution strengthening adds

1. A only surface paint ✓
2. B only lubricant oil ✓
3. C only vacuum ✓
4. D solute atoms distorting lattice and impeding dislocations ✓

Work hardening (strain hardening) increases strength by

1. A dislocation density increase during plastic deformation ✓
2. B grain growth in annealing ✓
3. C removing all dislocations ✓
4. D only heating above melting point ✓

Recrystallization annealing after cold work

1. A increases dislocation density further ✓
2. B forms new strain-free grains ✓
3. C converts metal to gas ✓
4. D only hardens surface by quench ✓

Brinell hardness test uses

1. A diamond pyramid only always ✓
2. B spring hammer rebound only ✓
3. C ultrasonic pulse only ✓
4. D hardened steel or carbide ball indenter ✓

Rockwell hardness differs from Brinell by

1. A measuring only scratch width optically always ✓
2. B using only Charpy hammer ✓
3. C measuring only electrical resistance ✓
4. D measuring depth of penetration under load ✓

Vickers hardness uses

1. A steel ball 10 mm only ✓
2. B single scratch line only ✓
3. C pendulum rebound only ✓
4. D square-based diamond pyramid indenter ✓

NDT method ultrasonic testing detects

1. A only surface colour ✓
2. B only chemical composition quantitatively always ✓
3. C internal flaws using sound wave reflection ✓
4. D only magnetic personality ✓

Radiographic testing (RT) uses

1. A X-rays or gamma rays to image internal defects ✓
2. B only visible light photography of surface ✓
3. C only hammer ringing always ✓
4. D only acid etching macro only ✓

Intergranular corrosion follows

1. A only crystal interiors uniformly ✓
2. B grain boundaries preferentially ✓
3. C only external paint failure ✓
4. D only magnetic domains ✓

Pitting corrosion is

1. A uniform thickness loss only ✓
2. B only intergranular cracking always ✓
3. C localized attack forming small cavities ✓
4. D only high-temperature oxidation ✓

Galvanic corrosion requires

1. A only one metal isolated in dry air ✓
2. B only plastic contact ✓
3. C electrochemically dissimilar metals in common electrolyte with conductive path ✓
4. D only identical metals touching in oil ✓

Corrosion fatigue combines

1. A only dry wear ✓
2. B cyclic loading and corrosive environment ✓
3. C only static tensile load in vacuum ✓
4. D only thermal expansion ✓

Endurance limit (fatigue limit) exists for

1. A all plastics always ✓
2. B all ceramics at room temperature always ✓
3. C many ferrous alloys under reversed stress ✓
4. D no materials ever ✓

Fatigue failure occurs under

1. A only single overload above UTS ✓
2. B only at cryogenic temperatures always ✓
3. C cyclic stresses below static yield strength ✓
4. D only compressive static load ✓

Creep is

1. A instant elastic stretch only ✓
2. B fatigue at room temperature only ✓
3. C time-dependent plastic deformation under constant stress at high temperature ✓
4. D hardness test indentation ✓

Cupronickel alloys resist

1. A seawater corrosion ✓
2. B only organic acids in food only always ✓
3. C zero corrosion in all acids ✓
4. D only high-temperature creep in gas turbines alone ✓

Magnetic particle inspection requires

1. A only aluminium alloys always ✓
2. B ferromagnetic material ✓
3. C only plastics ✓
4. D only ceramics always ✓

Dye penetrant inspection finds

1. A surface-breaking defects ✓
2. B only internal voids deep inside always without surface opening ✓
3. C only magnetic domains ✓
4. D only thermal conductivity ✓

Eddy current testing is best for

1. A only concrete structures ✓
2. B only wood timber ✓
3. C only glass only ✓
4. D detecting surface and near-surface flaws in conductive materials ✓

CCT diagram is more useful than TTT for

1. A only isothermal holding forever ✓
2. B only tensile testing speed ✓
3. C only hardness of rubber ✓
4. D continuous cooling processes like actual quenching ✓

Bainite microstructure forms at

1. A only instant quench to martensite always ✓
2. B only equilibrium slow cooling ✓
3. C only gas phase ✓
4. D intermediate temperature below pearlite nose on TTT ✓

Superalloys are used in

1. A only window glass ✓
2. B only concrete reinforcement bars at room service only ✓
3. C only paper production only ✓
4. D gas turbine hot sections for creep and oxidation resistance ✓

Ductile (nodular) cast iron obtains graphite shape by

1. A rapid oil quench only ✓
2. B adding magnesium or cerium inoculant ✓
3. C removing all carbon ✓
4. D sand casting without cores only ✓

White cast iron has carbon as

1. A graphite flakes only ✓
2. B graphite nodules only ✓
3. C no iron carbide ✓
4. D cementite without free graphite ✓

Stainless steel resists corrosion primarily due to

1. A chromium forming passive oxide film (typically ≥11% Cr) ✓
2. B high carbon only ✓
3. C lead content ✓
4. D zinc coating only ✓

Annealing heat treatment purpose is to

1. A maximize hardness always ✓
2. B soften metal, relieve stress and refine grain structure ✓
3. C form martensite always ✓
4. D increase internal stress ✓

Normalizing involves heating above Ac₃ and cooling in

1. A furnace at 1°C/hour ✓
2. B oil quench ✓
3. C liquid nitrogen ✓
4. D still air ✓

Tempering of martensite

1. A increases carbon in martensite by diffusion always instantly ✓
2. B eliminates all iron ✓
3. C reduces brittleness and internal stress while lowering hardness somewhat ✓
4. D converts to liquid ✓

Carburizing adds carbon to surface using

1. A only water quench ✓
2. B only sand blasting ✓
3. C carbon-rich atmosphere or pack at elevated temperature ✓
4. D only anodizing ✓

Nitriding forms hard surface by

1. A adding sulphur only ✓
2. B removing all carbon ✓
3. C electroplating copper only ✓
4. D diffusing nitrogen into steel (often alloy steels) ✓

Grey cast iron microstructure contains

1. A graphite flakes in ferrite/pearlite matrix ✓
2. B nodular graphite spheres primarily ✓
3. C no graphite ✓
4. D only martensite ✓

Brass is an alloy of

1. A copper and zinc ✓
2. B copper and tin only ✓
3. C iron and carbon ✓
4. D aluminium and magnesium only ✓

Austenitic stainless steels (300 series) are

1. A always martensitic BCC ✓
2. B pure iron only ✓
3. C non-magnetic FCC with nickel and chromium ✓
4. D always cast iron ✓

Martensitic stainless steels are

1. A hardenable by heat treatment; magnetic ✓
2. B always non-magnetic FCC ✓
3. C cannot be quenched ✓
4. D contain no chromium ✓

Aluminium alloys are often strengthened by

1. A only carburizing ✓
2. B only nitriding ✓
3. C precipitation hardening (age hardening) ✓
4. D only white iron formation ✓

Ultimate tensile strength is

1. A stress at fracture always on same scale ✓
2. B elastic limit only ✓
3. C hardness number in Brinell ✓
4. D maximum stress on engineering stress-strain curve ✓

Ductility is often expressed by

1. A percent elongation or reduction in area ✓
2. B Young's modulus value ✓
3. C melting point in Kelvin ✓
4. D thermal conductivity only ✓

Brittle fracture shows

1. A little plastic deformation before failure ✓
2. B necking and cup-cone fracture always ✓
3. C 50% elongation minimum ✓
4. D only ductile dimple rupture ✓

Charpy impact test measures

1. A energy absorbed by notched specimen at given temperature ✓
2. B surface roughness Ra ✓
3. C electrical resistivity ✓
4. D magnetic permeability only ✓

Iron-carbon equilibrium diagram eutectoid point is at

1. A 4.3% C at 1147°C ✓
2. B 0% C at 1538°C ✓
3. C 0.76% C at 727°C ✓
4. D 2.11% C at 727°C ✓

Pearlite microstructure consists of

1. A only austenite grains ✓
2. B alternating lamellae of ferrite and cementite ✓
3. C only martensite plates ✓
4. D only graphite flakes ✓

Cementite chemical formula is

1. A Fe₃C ✓
2. B FeO ✓
3. C Fe₂O₃ ✓
4. D Fe₃O₄ ✓

Austenite is

1. A BCC ferrite at room temperature ✓
2. B only liquid iron ✓
3. C only cementite plates ✓
4. D solid solution of carbon in gamma iron (FCC) ✓

Martensite is formed by

1. A slow furnace cooling only ✓
2. B hot rolling only ✓
3. C rapid quenching of austenite ✓
4. D annealing above 1000°C for days ✓

Hardenability measures

1. A only surface hardness of aluminium ✓
2. B depth to which steel hardens upon quenching ✓
3. C only copper conductivity ✓
4. D only cast iron graphite size ✓

Young's modulus measures

1. A stiffness in elastic region (stress/strain slope) ✓
2. B plastic ductility only ✓
3. C hardness indentation only ✓
4. D thermal expansion only ✓

Yield strength is the stress at which

1. A fracture occurs always ✓
2. B material begins significant plastic deformation ✓
3. C elastic limit is undefined always ✓
4. D creep starts at all temperatures ✓

Slip in crystals occurs on

1. A random planes only ✓
2. B close-packed planes in close-packed directions ✓
3. C only grain boundaries always ✓
4. D only external surfaces ✓

Dislocation is

1. A a surface scratch only ✓
2. B a line defect in crystal lattice responsible for plastic deformation ✓
3. C a gas bubble in casting only ✓
4. D a type of grain boundary ✓

Hall-Petch relation indicates yield strength increases as

1. A grain size decreases ✓
2. B grain size increases ✓
3. C temperature increases ✓
4. D strain rate decreases always ✓

Grain boundaries in polycrystalline metals are

1. A regions of perfect single crystal ✓
2. B only surface oxide layers ✓
3. C interfaces between crystals with different orientations ✓
4. D molten metal pools ✓

Coordination number in FCC is

1. A 8 ✓
2. B 6 ✓
3. C 4 ✓
4. D 12 ✓

Hexagonal close-packed (HCP) structure is common in

1. A copper and aluminium primarily ✓
2. B zinc, magnesium and titanium at room temperature ✓
3. C pure iron at all temperatures ✓
4. D lead only ✓

Face-centered cubic (FCC) structure has atoms at

1. A body center only with corners ✓
2. B only one corner ✓
3. C only edge centers ✓
4. D corners and face centers ✓

Body-centered cubic (BCC) structure has atoms at

1. A corners and face centers only ✓
2. B corners and body center of the cube ✓
3. C face centers only ✓
4. D edge midpoints only ✓

Unit cell is

1. A a biological cell in plants ✓
2. B a pressure vessel compartment only ✓
3. C the smallest repeating structural unit of a crystal lattice ✓
4. D a hydraulic cylinder chamber only ✓