Engineering Materials

The energy required to initiate a reaction, such as diffusion

Activation Energy

________________ can be defined as the quantity of mass diffusing through and perpendicular to a unit cross-sectional area of material per unit time.

Activation Energy

Which of the following one is not an imperfection in a crystalline solid structure.

Allotropy

In a(n) ______________ structure, there is two atoms per unit cell.

BCC

A(n) ______________ solid is one that has long range-order, in other words atoms are positioned in orderly and repeated patterns.

crystalline

Formation of substitutional solid solutions depend on some conditions and it is defined as Hume-Rotary Rule. Which of the following parameter is not mentioned in this rule?

Density

Which of the following properties is not influenced by the number of valance electrons?

Density

Considering two solid mediums, ____________ is the mass transport by atomic motion.

Diffusion

A mode of fracture attended by extensive gross plastic deformation.

Ductile Fracture

A measure of a material's ability to undergo appreciable plastic deformation before fracture.

Ductility

The highest stiff material in the below table is ______________________

E

Which of the following one is not attributes of metals in general consideration.

Electrical insulator

There is ______________ between two adjacent atoms such that each atom assumes a stable electron configuration in a covalent bonding.

Electron Sharing

The percent ionic character of a covalent-ionic mixed bond between two elements depends on their _____________

Electronegativity

The change in gauge length of a specimen (in the direction of an applied stress) divided by its original gauge length.

Engineering

pearlite for which the alternating ferrite and cementite layers are relatively thin

fine- pearlite

For the ____________ structure, the atomic packing factor is 0.74, which is the maximum packing possible for spheres all having the same diameter

FCC

In a(n) ______________ structure, there is four atoms per unit cell.

FCC

An interstitial defect is a linear or one-dimensional defect around which some of the atoms are misaligned.

False

Hot working is the plastic deformation of a metal at a temperature below that at which it recrystallizes.

False

If the diffusion flux is independent of time it's called non-steady state diffusion.

False

Linear density shows the number of atoms centered on a plane per area of plane

False

Self-diffusion can be defined as diffusion of atoms of one metal into another metal.

False

Failure, at relatively low stress levels, of structures that are subjected to fluctuating and cyclic stresses.

Fatigue

The maximum stress level that a material can sustain without failing, for some specified number of cycles.

Fatigue Strength

There is electrostatic attraction between oppositely charged ______________.

Ions

Which of the following one is not attributes of ceramics in general consideration.

Low melting point

What type of bonding would be expected for brass (a copper-zinc alloy)?

Metallic Bonding

Which of the following term can be considered as a measurement of ductility?

Percent Elongation

Deformation that is permanent or nonrecoverable after release of the applied load. It is accompanied by permanent atomic displacements.

Plastic deformation

What is the material class that is commonly formed by two or more combination of elements such as H, C, N, O, F or Si?

Polymers

A steel alloy that is highly resistant to corrosion in a variety of environments. The predominant alloying element is chromium, which must be present in a concentration of at least 11 wt%; other alloy additions, including nickel and molybdenum, are also possible.

Stainless Steel

Which of the following materials is a good example of crystalline solids?

Stainless Steel

The increase in hardness and strength of a ductile metal as it is plastically deformed below its recrystallization temperature.

Strain hardening

The equilibrium number of vacancies closely depend on the following parameter

Temperature

The addition of impurity atoms to a metal will result in the formation of _______________ and/or a new second phase, depending on the kinds of impurity, their concentrations, and the temperature of the alloy.

a solid solution

An austenitic transformation product found in some steels and cast irons. It forms at temperatures between those at which pearlite and martensite transformations occur. The microstructure consists of α-ferrite and a fine dispersion of cementite.

bainite

Pearlite for which the alternating ferrite and cementite layers are relatively thick.

coarse- pearlite

Fracture that occurs by rapid crack propagation and without appreciable macroscopic deformation.

Brittle Fracture

A copper-rich copper-tin alloy; aluminum, silicon, and nickel bronzes are also possible.

Bronze

A ferrous alloy in which carbon is the prime alloying element.

Carbon Steel

Hardening of the outer surface (or Case) of a steel component by a carburizing or nitriding process; used to improve wear and fatigue resistance.

Case Hardening

Generically, a ferrous alloy, the carbon content of which is greater than the maximum solubility in austenite at the eutectic temperature. Most commercial cast irons contain between 3.0 and 4.5 wt% C and between 1 and 3 wt% Si

Cast Iron

A combination of one or more metallic elements such as Al, Fe, Cr, Mo, with one or more nonmetallic elements such as C, N, O, P, S, forms _____________

Ceramics

What class of material could be the correct choice for high temperature applications.

Ceramics

A type of failure that results from the simultaneous action of a cyclic stress and chemical attack.

Corrosion Fatigue

The time-dependent permanent deformation that occurs under stress; for most materials it is important only at elevated temperatures.

Creep

The shear stress, resolved within a slip plane and direction, required to initiate slip.

Critical resolved shear stress

The highest strong material in the below table is ______________________

D

A metal alloy for which iron is the prime constituent.

Ferrous Alloy

For the steady state diffusion situations, the diffusion flux is proportional to the concentration gradient. This relationship is called

Fick's First Law

The mathematics for non-steady state may be described by ______________________

Fick's Second Law

___________________ equation requires to use erf (error function) for the solution.

Fick's Second Law

A technique of fracture analysis used to determine the stress level at which preexisting cracks of known size will propagate, leading to fracture.

Fracture Mechanics

The measure of a material's resistance to fracture when a crack is present.

Fracture Toughness (Kc)

Depend on their bonding energy, metals are generally known with their moderate melting temperature, moderate elasticity modules and moderate thermal expansion, on the contrary Ceramics possess ___________

High Melting Temperature

The nucleus of an atom contains which of the following?

Protons

The relief of some of the internal strain energy of a previously cold-worked metal, usually by heat treatment.

Recovery

The formation of a new set of strain-free grains within a previously cold-worked material; normally, an annealing heat treatment is necessary.

Recrystallization

For a particular alloy, the minimum temperature at which complete recrystallization occurs within approximately 1 h.

Recrystallization temperature

The capacity of a material to absorb energy when it is elastically deformed.

Resilience

An applied tensile or compressive stress resolved into a shear component along a specific plane and direction within that plane.

Resolved shear stress

Which of the following is a dislocation type?

Screw

The advanced materials that are used in high-tech applications, including ___________ having electrical conductivities intermediate between those of conductors and insulators.

Semiconductors

Plastic deformation as the result of dislocation motion; also, the shear displacement of two adjacent planes of atoms.

Slip

The combination of a crystallographic plane and, within that plane, a crystallographic direction along which slip (i.e., dislocation motion) occurs.

Slip system

The advanced materials that are used in high-tech applications, including ____________ those that sense and respond to changes in their environments in predetermined manners.

Smart Materials

There are four elements to consider—processing, structure, properties, and performance. _______________ of a material depends on its properties, which in turn are a function of its structure(s); furthermore, structure(s) is (are) determined by how the material was processed.

The performance

Adding "impurity" atoms to Cu decreases ____________

Thermal Resistivity

The ability of a material to absorb energy and plastically deform before fracturing in other words the total area under the material's tensile engineering stress-strain curve taken to fracture

Toughness

Carburizing can be defined as the process by which the surface carbon concentration of a ferrous alloy is increased by diffusion from the surrounding environment.

True

Hardening and strengthening of metals that result from alloying in which a solid solution is formed. The presence of impurity atoms restricts dislocation mobility. It's called solid-solution strengthening.

True

Practically, it is not possible to produce a perfect crystalline solid that does not contain any defect.

True

The crystal structure and interplanar spacing can be determined by using X-ray diffraction.

True

The instantaneous applied load divided by the instantaneous cross-sectional area of a specimen.

True Stress

The natural logarithm of the ratio of instantaneous gauge length to original gauge length of a specimen being deformed by a uniaxial force.

True strain

In a metallic bonding structure, the positively charged ion cores are shielded from one another, and also "glued" together by the sea of ______________.

Valance Electrons

The electrons that occupy the outermost filled shell are called __________________.

Valance Electrons

Iron (Fe) undergoes a(n) ______________ transformation at 912oC upon heating from a BCC (α phase) to an FCC (γ phase)

allotropic

A ferrous (or iron-based) alloy that contains appreciable concentrations of alloying elements (other than C and residual amounts of Mn, Si, S, and P). These alloying elements are usually added to improve mechanical and corrosion-resistance properties.

alloy steel

Conventional window glass is an example of a(n) ______________ solid.

amorphous

___________________ defects happen when impurity atoms with much smaller than host atoms fill the gaps in the host atoms.

interstitial

What is the unit of diffusion coefficient?

m^2/s

A metastable iron phase supersaturated in carbon that is the product of a diffusionless (athermal) transformation from austenite.

martensite

A change in the number and/or character of the phases that constitute the microstructure of an alloy.

phase transformation

Which of the following material can be considered as isotropic?

polycrystalline iron

The ____________ is an element or compound present in a minor concentration. The _________ is the element or compound present in the greatest amount.

solute / solvent

A high degree of substitutional solid solubility of one atom type in another is possible when ___________________ rules are obeyed.

the Hume-Rothery

A ______________ is the smallest component of the crystal that reproduces the whole crystal when stacked together with purely translational repetition

unit cell

What type of bonding would be expected for a rubber, particularly between the molecular chains?

van der Waals Bonding