Engineering Materials and Metallurgy MCQs 2026

Bronze traditionally is alloy of

1. Acopper and tin✓
2. Bcopper and zinc✓
3. Ciron and nickel✓
4. Dlead and tin only✓

Pearlite lamella spacing affects

1. Aonly electrical resistivity of copper wire✓
2. Bstrength and hardness with finer spacing giving higher strength✓
3. Conly paint viscosity✓
4. Donly air density at altitude✓

Passivation of stainless steel uses

1. Anitric or citric acid treatment to strengthen oxide film✓
2. Bmolten zinc dip only✓
3. Ccarburizing gas✓
4. Dsand blasting only✓

Brass is an alloy of

1. Acopper and zinc✓
2. Bcopper and tin only✓
3. Ciron and carbon✓
4. Daluminium and magnesium only✓

Zinc coating on steel sheet is called

1. Atinning only always✓
2. Banodizing✓
3. Cgalvanizing✓
4. Dchromating only on aluminium✓

Curie temperature of iron is about

1. A770°C where ferromagnetism is lost✓
2. B27°C✓
3. C1538°C melting point✓
4. D1147°C eutectic✓

Allotropy of iron means

1. Airon never changes structure✓
2. Biron exists in different crystal structures (BCC and FCC) at different temperatures✓
3. Ciron is only liquid at room temperature✓
4. Diron has no carbon solubility✓

Recrystallization temperature for metals is approximately

1. A0.3 to 0.5 times absolute melting temperature✓
2. Btwice melting point✓
3. Croom temperature always for steel✓
4. Dzero kelvin✓

Cold shortness is associated with

1. Aonly high temperature forging✓
2. Bexcess phosphorus making steel brittle at low temperature✓
3. Conly austenite stability✓
4. Donly copper plating✓

Hot shortness in metals is cracking during hot work due to

1. Alow-melting grain boundary films (e.g. copper in steel)✓
2. Bonly cold temperature✓
3. Conly high hardness✓
4. Donly magnetic fields✓

Sintering temperature in PM is

1. Aalways above liquidus✓
2. Bat room temperature only✓
3. Cbelow melting point of main constituent✓
4. Dabove boiling point✓

Powder metallurgy process sequence is typically

1. Acasting, forging, welding only✓
2. Bonly electroplating✓
3. Conly extrusion of billet✓
4. Dpowder production, compaction, sintering✓

Stress corrosion cracking needs

1. Aonly compression in dry nitrogen✓
2. Bonly cyclic impact in vacuum✓
3. Conly annealing temperature✓
4. Dtensile stress, susceptible alloy and corrosive medium together✓

Intergranular corrosion follows

1. Aonly crystal interiors uniformly✓
2. Bgrain boundaries preferentially✓
3. Conly external paint failure✓
4. Donly magnetic domains✓

Pitting corrosion is

1. Auniform thickness loss only✓
2. Bonly intergranular cracking always✓
3. Clocalized attack forming small cavities✓
4. Donly high-temperature oxidation✓

Galvanic corrosion requires

1. Aonly one metal isolated in dry air✓
2. Bonly plastic contact✓
3. Celectrochemically dissimilar metals in common electrolyte with conductive path✓
4. Donly identical metals touching in oil✓

Corrosion fatigue combines

1. Aonly dry wear✓
2. Bcyclic loading and corrosive environment✓
3. Conly static tensile load in vacuum✓
4. Donly thermal expansion✓

Endurance limit (fatigue limit) exists for

1. Aall plastics always✓
2. Ball ceramics at room temperature always✓
3. Cmany ferrous alloys under reversed stress✓
4. Dno materials ever✓

Fatigue failure occurs under

1. Aonly single overload above UTS✓
2. Bonly at cryogenic temperatures always✓
3. Ccyclic stresses below static yield strength✓
4. Donly compressive static load✓

Creep is

1. Ainstant elastic stretch only✓
2. Bfatigue at room temperature only✓
3. Ctime-dependent plastic deformation under constant stress at high temperature✓
4. Dhardness test indentation✓

Cupronickel alloys resist

1. Aseawater corrosion✓
2. Bonly organic acids in food only always✓
3. Czero corrosion in all acids✓
4. Donly high-temperature creep in gas turbines alone✓

Hexagonal close-packed (HCP) structure is common in

1. Acopper and aluminium primarily✓
2. Bzinc, magnesium and titanium at room temperature✓
3. Cpure iron at all temperatures✓
4. Dlead only✓

Unit cell is

1. Aa biological cell in plants✓
2. Ba pressure vessel compartment only✓
3. Cthe smallest repeating structural unit of a crystal lattice✓
4. Da hydraulic cylinder chamber only✓

Body-centered cubic (BCC) structure has atoms at

1. Acorners and face centers only✓
2. Bcorners and body center of the cube✓
3. Cface centers only✓
4. Dedge midpoints only✓

Face-centered cubic (FCC) structure has atoms at

1. Abody center only with corners✓
2. Bonly one corner✓
3. Conly edge centers✓
4. Dcorners and face centers✓

Coordination number in FCC is

1. A8✓
2. B6✓
3. C4✓
4. D12✓

Grain boundaries in polycrystalline metals are

1. Aregions of perfect single crystal✓
2. Bonly surface oxide layers✓
3. Cinterfaces between crystals with different orientations✓
4. Dmolten metal pools✓

Hall-Petch relation indicates yield strength increases as

1. Agrain size decreases✓
2. Bgrain size increases✓
3. Ctemperature increases✓
4. Dstrain rate decreases always✓

Dislocation is

1. Aa surface scratch only✓
2. Ba line defect in crystal lattice responsible for plastic deformation✓
3. Ca gas bubble in casting only✓
4. Da type of grain boundary✓

Slip in crystals occurs on

1. Arandom planes only✓
2. Bclose-packed planes in close-packed directions✓
3. Conly grain boundaries always✓
4. Donly external surfaces✓

Young's modulus measures

1. Astiffness in elastic region (stress/strain slope)✓
2. Bplastic ductility only✓
3. Chardness indentation only✓
4. Dthermal expansion only✓

Yield strength is the stress at which

1. Afracture occurs always✓
2. Bmaterial begins significant plastic deformation✓
3. Celastic limit is undefined always✓
4. Dcreep starts at all temperatures✓

Ultimate tensile strength is

1. Astress at fracture always on same scale✓
2. Belastic limit only✓
3. Chardness number in Brinell✓
4. Dmaximum stress on engineering stress-strain curve✓

Ductility is often expressed by

1. Apercent elongation or reduction in area✓
2. BYoung's modulus value✓
3. Cmelting point in Kelvin✓
4. Dthermal conductivity only✓

Brittle fracture shows

1. Alittle plastic deformation before failure✓
2. Bnecking and cup-cone fracture always✓
3. C50% elongation minimum✓
4. Donly ductile dimple rupture✓

Charpy impact test measures

1. Aenergy absorbed by notched specimen at given temperature✓
2. Bsurface roughness Ra✓
3. Celectrical resistivity✓
4. Dmagnetic permeability only✓

Iron-carbon equilibrium diagram eutectoid point is at

1. A4.3% C at 1147°C✓
2. B0% C at 1538°C✓
3. C0.76% C at 727°C✓
4. D2.11% C at 727°C✓

Pearlite microstructure consists of

1. Aonly austenite grains✓
2. Balternating lamellae of ferrite and cementite✓
3. Conly martensite plates✓
4. Donly graphite flakes✓

Cementite chemical formula is

1. AFe₃C✓
2. BFeO✓
3. CFe₂O₃✓
4. DFe₃O₄✓

Austenite is

1. ABCC ferrite at room temperature✓
2. Bonly liquid iron✓
3. Conly cementite plates✓
4. Dsolid solution of carbon in gamma iron (FCC)✓

Martensite is formed by

1. Aslow furnace cooling only✓
2. Bhot rolling only✓
3. Crapid quenching of austenite✓
4. Dannealing above 1000°C for days✓

Hardenability measures

1. Aonly surface hardness of aluminium✓
2. Bdepth to which steel hardens upon quenching✓
3. Conly copper conductivity✓
4. Donly cast iron graphite size✓

Normalizing involves heating above Ac₃ and cooling in

1. Afurnace at 1°C/hour✓
2. Boil quench✓
3. Cliquid nitrogen✓
4. Dstill air✓

Tempering of martensite

1. Aincreases carbon in martensite by diffusion always instantly✓
2. Beliminates all iron✓
3. Creduces brittleness and internal stress while lowering hardness somewhat✓
4. Dconverts to liquid✓

Carburizing adds carbon to surface using

1. Aonly water quench✓
2. Bonly sand blasting✓
3. Ccarbon-rich atmosphere or pack at elevated temperature✓
4. Donly anodizing✓

Nitriding forms hard surface by

1. Aadding sulphur only✓
2. Bremoving all carbon✓
3. Celectroplating copper only✓
4. Ddiffusing nitrogen into steel (often alloy steels)✓

Grey cast iron microstructure contains

1. Agraphite flakes in ferrite/pearlite matrix✓
2. Bnodular graphite spheres primarily✓
3. Cno graphite✓
4. Donly martensite✓

Ductile (nodular) cast iron obtains graphite shape by

1. Arapid oil quench only✓
2. Badding magnesium or cerium inoculant✓
3. Cremoving all carbon✓
4. Dsand casting without cores only✓

White cast iron has carbon as

1. Agraphite flakes only✓
2. Bgraphite nodules only✓
3. Cno iron carbide✓
4. Dcementite without free graphite✓

Stainless steel resists corrosion primarily due to

1. Achromium forming passive oxide film (typically ≥11% Cr)✓
2. Bhigh carbon only✓
3. Clead content✓
4. Dzinc coating only✓

Segregation in castings causes

1. Aperfect homogeneity always✓
2. Bonly surface polish✓
3. Conly magnetic alignment✓
4. Dnon-uniform composition and properties✓

Aluminium alloys are often strengthened by

1. Aonly carburizing✓
2. Bonly nitriding✓
3. Cprecipitation hardening (age hardening)✓
4. Donly white iron formation✓

Martensitic stainless steels are

1. Ahardenable by heat treatment; magnetic✓
2. Balways non-magnetic FCC✓
3. Ccannot be quenched✓
4. Dcontain no chromium✓

Inoculation in cast iron promotes

1. Aonly cementite formation always✓
2. Bonly gas porosity✓
3. Conly martensite in cast iron✓
4. Dgraphite nucleation for desired graphite form✓

Thermosetting plastics once cured

1. Asoften reversibly like wax always✓
2. Bbecome metals✓
3. Ccannot be re-melted without degradation✓
4. Devaporate instantly✓

Thermoplastics can be

1. Aonly cured irreversibly like thermosets always✓
2. Bre-melted and reshaped repeatedly✓
3. Conly used as liquids always✓
4. Dnever injection moulded✓

Glass transition temperature Tg of polymer is

1. Amelting of iron carbide✓
2. Bboiling of water✓
3. Ctemperature where amorphous polymer becomes rubbery on heating✓
4. DCurie point of nickel only✓

Fiber direction in composites primarily controls

1. Aisotropic behaviour in all directions always✓
2. Bonly colour✓
3. Canisotropic strength and stiffness✓
4. Donly density reduction only✓

Composite materials combine

1. Aonly single pure element always✓
2. Bmatrix and reinforcement for tailored properties✓
3. Conly water and oil✓
4. Donly one grain boundary✓

Titanium alloys advantage is

1. Ahigh strength-to-weight ratio and corrosion resistance✓
2. Blowest melting point of all metals✓
3. Calways cheaper than mild steel✓
4. Dcannot be welded ever✓

Superalloys are used in

1. Aonly window glass✓
2. Bonly concrete reinforcement bars at room service only✓
3. Conly paper production only✓
4. Dgas turbine hot sections for creep and oxidation resistance✓

Bainite microstructure forms at

1. Aonly instant quench to martensite always✓
2. Bonly equilibrium slow cooling✓
3. Conly gas phase✓
4. Dintermediate temperature below pearlite nose on TTT✓

CCT diagram is more useful than TTT for

1. Aonly isothermal holding forever✓
2. Bonly tensile testing speed✓
3. Conly hardness of rubber✓
4. Dcontinuous cooling processes like actual quenching✓

Austenitic stainless steels (300 series) are

1. Aalways martensitic BCC✓
2. Bpure iron only✓
3. Cnon-magnetic FCC with nickel and chromium✓
4. Dalways cast iron✓

Eddy current testing is best for

1. Aonly concrete structures✓
2. Bonly wood timber✓
3. Conly glass only✓
4. Ddetecting surface and near-surface flaws in conductive materials✓

Dye penetrant inspection finds

1. Asurface-breaking defects✓
2. Bonly internal voids deep inside always without surface opening✓
3. Conly magnetic domains✓
4. Donly thermal conductivity✓

Magnetic particle inspection requires

1. Aonly aluminium alloys always✓
2. Bferromagnetic material✓
3. Conly plastics✓
4. Donly ceramics always✓

Radiographic testing (RT) uses

1. AX-rays or gamma rays to image internal defects✓
2. Bonly visible light photography of surface✓
3. Conly hammer ringing always✓
4. Donly acid etching macro only✓

NDT method ultrasonic testing detects

1. Aonly surface colour✓
2. Bonly chemical composition quantitatively always✓
3. Cinternal flaws using sound wave reflection✓
4. Donly magnetic personality✓

Vickers hardness uses

1. Asteel ball 10 mm only✓
2. Bsingle scratch line only✓
3. Cpendulum rebound only✓
4. Dsquare-based diamond pyramid indenter✓

Rockwell hardness differs from Brinell by

1. Ameasuring only scratch width optically always✓
2. Busing only Charpy hammer✓
3. Cmeasuring only electrical resistance✓
4. Dmeasuring depth of penetration under load✓

Brinell hardness test uses

1. Adiamond pyramid only always✓
2. Bspring hammer rebound only✓
3. Cultrasonic pulse only✓
4. Dhardened steel or carbide ball indenter✓

Recrystallization annealing after cold work

1. Aincreases dislocation density further✓
2. Bforms new strain-free grains✓
3. Cconverts metal to gas✓
4. Donly hardens surface by quench✓

Work hardening (strain hardening) increases strength by

1. Adislocation density increase during plastic deformation✓
2. Bgrain growth in annealing✓
3. Cremoving all dislocations✓
4. Donly heating above melting point✓

Solid solution strengthening adds

1. Aonly surface paint✓
2. Bonly lubricant oil✓
3. Conly vacuum✓
4. Dsolute atoms distorting lattice and impeding dislocations✓

Lever rule on phase diagram calculates

1. Ahardness from cooling rate✓
2. Bmass fractions of two phases in two-phase region✓
3. Celectrical conductivity only✓
4. Dsurface tension only✓

Phase diagram horizontal line indicates

1. Avariable composition single phase only✓
2. Bimpossible equilibrium✓
3. Conly mechanical mixing✓
4. Dinvariant reaction (eutectic, eutectoid or peritectic)✓

Annealing heat treatment purpose is to

1. Amaximize hardness always✓
2. Bsoften metal, relieve stress and refine grain structure✓
3. Cform martensite always✓
4. Dincrease internal stress✓