Engineering Materials — Engineering Board Exam Reviewer

200 free Engineering Materials practice questions for the Philippine Engineering Board Exam, each with the correct answer and a worked solution.

Intrinsic silicon at room temperature has 1 × 1016 electrons/m³ (and the same number of holes), with e = 0.14 and h = 0.05 m2/V· s. What…
A steel structure corrodes with a constant corrosion current of 0.01 A. How much iron (Fe Fe2+ + 2e-) is lost in one year? (Fe = 55.85…
A steel plate ( = 7.9 g/cm3) with an exposed area of 645 cm2 loses 485 g to uniform corrosion in one year (8760 h). What is the corrosion…
A component is cyclically loaded between a maximum stress of 200 MPa and a minimum stress of −50 MPa. What are the stress amplitude and…
Using the Hall–Petch equation y = 0 + ky d-1/2 with 0 = 70 MPa and ky = 0.74 MPa · sqrt(m), what is the yield strength for a grain…
A rod is cold drawn from a diameter of 15 mm to 12 mm. What is the percent cold work?
Carbon fibers (tensile strength 3.5 GPa, diameter 10 m) are embedded in a matrix with an interfacial shear strength of 40 MPa. What is the…
A slowly cooled hypoeutectoid steel contains 60% pearlite and 40% proeutectoid ferrite by mass. What is its approximate carbon content?…
For a hypereutectoid steel with 1.2% C cooled slowly to just below 727 °C, what is the mass fraction of proeutectoid cementite? (eutectoid…
For a 0.25% C steel just below 727 °C, what is the TOTAL mass fraction of ferrite (proeutectoid plus eutectoid)? (ferrite 0.022% C…
For a 0.25% C steel cooled slowly to just below 727 °C, what is the mass fraction of proeutectoid ferrite? (ferrite 0.022% C, eutectoid…
A Pb–40 wt% Sn alloy at 150 °C consists of (10 wt% Sn) and (98 wt% Sn). What is the mass fraction of the phase?
Molybdenum has an atomic radius of 0.1363 nm, an atomic weight of 95.94 g/mol and a measured density of 10.22 g/cm3. Which crystal…
What is the linear density of atoms along the [110] direction in copper (FCC, R = 0.128 nm)?
What is the planar density of atoms on the (100) plane of copper (FCC, a = 0.3615 nm)?
Copper has 8.0 × 1028 atoms/m³ and a vacancy formation energy of 0.9 eV/atom. How many vacancies per cubic meter exist at 1000 ° C? (k =…
The modulus of elasticity of most metals with increasing temperature generally:
Which property primarily determines a material's resistance to elastic deflection?
Stress concentrations at holes, notches and sharp corners are especially dangerous under:
The three stages of a typical creep curve are:
Hydrogen embrittlement in high-strength steels results in:
The fracture surface of a fatigue failure typically shows:
Welding of high-carbon steels is difficult mainly because:
Powder metallurgy involves:
Hot working is performed:
Cold working a metal generally:
Steel has E = 200 GPa and = 7.85 g/cm3; aluminum has E = 70 GPa and = 2.70 g/cm3. Which has the higher specific stiffness (E/ )?
Heat flows through a 100 mm thick polystyrene insulation panel (k = 0.05 W/m· K) of area 10 m2 with a temperature difference of 30 °C…
An aluminum rod (E = 70 GPa, = 23.6 × 10-6 /° C) is held between rigid supports and heated by 80 °C. What compressive thermal stress…
An aluminum bar 2 m long is heated by 80 °C. How much does it expand? ( = 23.6 × 10-6 /° C)
An n-type silicon sample has 1 × 1022 free electrons per m3 with an electron mobility of 0.14 m2/V· s. What is its electrical…
Copper has an electrical resistivity of 1.72 × 10-8 · m. What is its electrical conductivity?
If a carburized case 0.5 mm deep is obtained in 10 hours at a certain temperature, how long would it take to obtain a 1.0 mm case at the…
The diffusion of carbon in γ-iron has D0 = 2.3 × 10-5 m2/s and Q = 148 kJ/mol. What is the diffusion coefficient at 900 ° C? (R = 8.314…
Carbon diffuses through a steel plate 2 mm thick. The concentrations on the two faces are 5 kg/m3 and 1 kg/m3, and D = 1 × 10-11 m2/s…
According to the Gibbs phase rule (F = C - P + 2), at the triple point of a pure substance (C = 1, P = 3), the number of degrees of…
In a two-phase + L region, an alloy of 30% B lies on a tie line with at 10% B and liquid at 40% B. What is the mass fraction of ?
What is the mass fraction of cementite in pearlite (eutectoid steel, 0.76% C) just below 727 °C? (ferrite 0.022% C, cementite 6.70% C)
A 0.40% C steel is slowly cooled to just below 727 °C. What is the mass fraction of pearlite? (Use 0.022% C for ferrite and 0.76% C for…
A steel has a plane-strain fracture toughness of 50 MPa · sqrt(m). For a design stress of 300 MPa and Y = 1.0, what is the critical crack…
A steel plate with an edge crack 2 mm deep is loaded in tension at 200 MPa. Using K = 1.12 sqrt(π a), what is the stress intensity factor?
A structural steel with a yield strength of 250 MPa is designed with a factor of safety of 2.5. What is the allowable stress?
For steels, tensile strength ( MPa) 3.45 × BHN. What is the approximate tensile strength of a steel with a Brinell hardness of 229?
A Brinell test uses a 10 mm ball under a load of 3000 kgf and produces an indentation 4.0 mm in diameter. What is the Brinell hardness…
What is the maximum load a 10 mm diameter rod with an ultimate tensile strength of 500 MPa can carry?
What is the true strain corresponding to an engineering strain of 0.20?
At an engineering stress of 400 MPa, a specimen has an engineering strain of 0.20. Assuming constant volume, what is the true stress?
A steel has a yield strength of 250 MPa and a modulus of elasticity of 200 GPa. What is its modulus of resilience?
A tensile specimen with an original diameter of 12.8 mm has a diameter of 8.0 mm at the fracture neck. What is its percent reduction in…
Steel has E = 200 GPa and = 0.3. What is its bulk modulus?
Steel has E = 200 GPa and = 0.3. What is its shear modulus?
A material with Poisson's ratio 0.3 has an axial strain of 0.001 in tension. What is its lateral strain?
A steel rod 1.5 m long and 12 mm in diameter carries a tensile load of 20 kN. What is its elongation? (E = 200 GPa)
A material shows a stress of 150 MPa at a strain of 0.00075 in the elastic region. What is its modulus of elasticity?
A bar 2 m long elongates 1.5 mm under load. What is the engineering strain?
The number of slip systems in an FCC metal is:
In the FCC structure, the close-packed (most densely packed) planes belong to the family:
A plane parallel to the y and z axes that intercepts the x-axis at 1 has Miller indices:
What are the Miller indices of a plane that intercepts the axes at 1, 1, 1?
What are the Miller indices of a plane that intercepts the x, y and z axes at 1, 2 and ∞, respectively?
X-rays of wavelength 0.1542 nm are diffracted by planes with interplanar spacing 0.2087 nm. What is the diffraction angle 2 for…
For copper (FCC, a = 0.3615 nm), what is the interplanar spacing of the (111) planes?
Show that the atomic packing factor of the BCC structure equals:
What is the atomic packing factor of a simple cubic structure?
α-Iron is BCC with an atomic radius of 0.1241 nm and an atomic weight of 55.85 g/mol. What is its theoretical density?
Copper has an FCC structure with a lattice parameter of 0.3615 nm and an atomic weight of 63.55 g/mol. What is its theoretical density?
For a simple cubic structure, the relationship between the lattice parameter a and atomic radius R is:
Iron (BCC) has an atomic radius of 0.1241 nm. What is its lattice parameter?
Aluminum has an FCC structure with an atomic radius of 0.1431 nm. What is its lattice parameter?
Shape memory alloys such as Nitinol (Ni–Ti) can:
Materials that generate an electric charge when mechanically stressed are called:
Silicon steel is used for transformer cores mainly because it has:
Soft magnetic materials, used for transformer cores, are characterized by:
The temperature above which a ferromagnetic material becomes paramagnetic is called the:
Materials that are strongly attracted to magnets and can be permanently magnetized, such as iron, nickel and cobalt, are:
Doping silicon with boron produces a/an:
The electrical conductivity of a pure (intrinsic) semiconductor:
The band gap of silicon at room temperature is approximately:
Materials in which the valence band and conduction band overlap, allowing easy electron flow, are:
Which of the following metals is most noble (least likely to corrode) in the galvanic series in seawater?
Anodizing is a process used mainly to protect:
Cracking caused by the combined action of tensile stress and a corrosive environment is called:
Corrosion that occurs in narrow gaps such as under gaskets or bolt heads is called:
Localized corrosion that forms small holes or cavities on a metal surface is called:
In a steel–copper galvanic couple in seawater, which metal corrodes preferentially?
When two dissimilar metals are in electrical contact in an electrolyte, the corrosion of the more active metal accelerates. This is called:
In a longitudinally loaded composite with 60% fibers (Ef = 230 GPa) and 40% matrix (Em = 3.5 GPa), what percentage of the load is carried…
A composite contains 60% by volume carbon fibers ( = 1.8 g/cm3) in epoxy ( = 1.2 g/cm3). What is its density?
A unidirectional composite has 60% by volume carbon fibers (E = 230 GPa) in an epoxy matrix (E = 3.5 GPa). What is its transverse modulus…
A unidirectional composite has 60% by volume carbon fibers (E = 230 GPa) in an epoxy matrix (E = 3.5 GPa). What is its longitudinal…
In a fiber composite, the strength and stiffness are greatest when loaded:
Wood is a natural composite consisting mainly of:
Reinforced concrete is an example of a:
Increasing the degree of crystallinity of a polymer generally:
Additives that are mixed with polymers to increase their flexibility are called:
Kevlar is a high-strength fiber made from a/an:
Plexiglas (acrylic) is chemically:
Teflon is the trade name for:
A polymer made of two or more different types of monomers is called a:
The number of repeat units (mers) in a polymer chain is called the:
Polymers that can be stretched to large elastic strains and recover their shape, like rubber, are called:
Polymers that form a permanent cross-linked network on curing and cannot be remelted are called:
Polymers that soften on heating and can be remolded repeatedly are called:
Silicon carbide and tungsten carbide are commonly used as:
Gypsum is added to Portland cement to:
The hardening of Portland cement paste is mainly due to:
Portland cement is produced mainly by heating a mixture of:
Tempered glass is stronger than ordinary glass because:
The temperature at which an amorphous material changes from a rigid glass to a supercooled liquid/rubbery state is the:
Ceramics are generally much stronger in:
Compared with metals, ceramics generally have:
Titanium alloys are widely used in aerospace mainly because of their:
Invar, an iron–nickel alloy with about 36% Ni, is notable for its:
Monel metal is an alloy of:
Lead is sometimes added to steel and brass to improve:
The alloying element added to steel mainly to improve hardenability and toughness and to counteract sulfur's harmful effects is:
High-speed tool steels retain their hardness at high temperatures mainly due to alloying with:
Austenitic stainless steels such as type 304 contain about:
The AISI–SAE designation 4340 refers to a:
In the AISI–SAE steel designation 1045, the last two digits indicate:
White cast iron is hard and brittle because most of its carbon is present as:
Ductile (nodular) cast iron contains graphite in the form of:
Gray cast iron gets its name from the gray fracture surface caused by:
The Hume-Rothery rules describe the conditions for:
Which strengthening mechanism involves adding atoms of another element that dissolve in the host lattice?
Precipitation (age) hardening is commonly used to strengthen:
The heat treatment that restores the ductility of a cold-worked metal by forming new strain-free grains is called:
Strengthening a metal by plastic deformation at room temperature is called:
Prolonged heating of pearlitic steel just below the eutectoid temperature produces a very soft structure called:
Isothermal transformation of austenite at temperatures between those forming pearlite and martensite produces:
The ability of a steel to be hardened to a depth by quenching is called:
The diagram that shows the time needed for austenite to transform at a constant temperature is the:
Reheating quenched (martensitic) steel to a temperature below the eutectoid temperature to reduce brittleness is called:
Rapid cooling of steel from the austenite region in water, oil or brine is called:
Heating steel into the austenite region and cooling it in still air is called:
Heating steel into the austenite region and cooling it slowly in the furnace is called:
A steel with less than 0.76% carbon is called a:
The very hard, brittle microconstituent formed by rapidly quenching austenite is:
The lamellar mixture of ferrite and cementite formed by the eutectoid reaction in steel is called:
The BCC phase of iron (α-iron) at room temperature is called:
Iron carbide ( Fe3C) is also called:
The eutectic composition in the iron–iron carbide system is approximately:
The eutectoid temperature in the iron–iron carbide system is approximately:
In the iron–carbon system, the eutectoid composition is about:
A reaction in which one solid phase transforms into two other solid phases on cooling is called a/an:
The rule used to determine the relative amounts of phases in a two-phase region of a binary phase diagram is the:
A diagram that shows the phases present in an alloy system as a function of temperature and composition is called a:
The temperature below which a BCC metal such as steel changes from ductile to brittle behavior is called the:
The nondestructive test that detects surface and near-surface cracks in ferromagnetic materials using iron powder is:
A nondestructive test that uses high-frequency sound waves to detect internal flaws is:
The Vickers hardness test uses a:
The Brinell hardness test uses an indenter made of a:
The Charpy and Izod tests are used to measure:
The graph used to present fatigue data is called the:
The stress level below which a steel can endure an infinite number of load cycles without failure is called the:
The slow, time-dependent plastic deformation of a material under constant stress, usually at high temperature, is called:
For materials without a distinct yield point, the yield strength is commonly determined by the:
The maximum stress on an engineering stress–strain curve is the:
The slope of the elastic portion of a stress–strain curve is the:
A material that fractures with little or no plastic deformation is described as:
The ability of a material to absorb energy when deformed elastically and release it on unloading is called:
The ability of a material to absorb energy and plastically deform before fracturing is called:
The ability of a material to be hammered or rolled into thin sheets is called:
The ability of a material to deform plastically before fracture is called:
Nitriding is a surface hardening process in which:
The rate of diffusion in solids generally:
Fick's first law of diffusion states that the diffusion flux is proportional to the:
Grain boundaries are classified as:
Plastic deformation in crystalline metals occurs mainly by the movement of:
A dislocation is a type of:
A vacancy is a:
X-ray diffraction is used to determine:
The notation used to specify crystallographic planes is:
A material whose properties vary with crystallographic direction is said to be:
The ability of a material to exist in more than one crystal structure depending on temperature and pressure is called:
Which of the following metals has a BCC crystal structure at room temperature?
Which of the following metals has an FCC crystal structure at room temperature?
The atomic packing factor of a BCC structure is:
The atomic packing factor (APF) of an FCC structure is:
The coordination number of atoms in a BCC crystal structure is:
The number of atoms in an HCP unit cell (hexagonal prism) is:
The number of atoms per unit cell in a simple cubic (SC) structure is:
The number of atoms per unit cell in a face-centered cubic (FCC) structure is:
The number of atoms per unit cell in a body-centered cubic (BCC) structure is:
A solid that lacks long-range atomic order, such as glass, is called:
A solid in which atoms are arranged in a repeating, periodic three-dimensional pattern is called:
The metal with the highest electrical conductivity is:
The metal with the highest melting point is:
The density of steel is approximately:
The lightest structural metal commonly used in engineering is:
Steel is basically an alloy of:
Stainless steel resists corrosion mainly because it contains at least about:
Solder traditionally used in electronics is an alloy of:
Bronze is an alloy of:
Brass is an alloy of:
A metal mixed with one or more other elements to improve its properties is called a/an:
A material made of two or more distinct materials combined to obtain properties not achievable by either alone is called a:
Materials made of long chain-like molecules, often of carbon and hydrogen, are called:
Materials composed of metallic and nonmetallic elements bonded mainly by ionic and/or covalent bonds (e.g., oxides, carbides) are called:
The four major classes of engineering materials are: