Key Concepts in Materials Science and Engineering

Chromium

The primary alloying element in stainless steel that gives it corrosion resistance.

Strain hardening

Cold working generally leads to strain hardening.

Bulk deformation process

Includes rolling, forging, extrusion, wire/rod/tube drawing, cold forming (including impact extrusion), piercing, and squeezing processes (e.g., coining, hubbing).

Flux in welding

The primary function of flux in welding is to remove oxides.

Investment casting

The casting method that provides the best surface finish.

Toughness

The property to resist fracture.

Creep

Time-dependent deformation of a material under constant stress.

TIG

The welding method that uses a non-consumable electrode.

Zinc

The material most commonly used in die casting.

Isotropic material

Implies uniform properties in all directions.

Brittleness

The main disadvantage of ceramics.

Surface hardness

The property improved by carburizing steel.

Shot peening

The method used to improve fatigue resistance in components.

Tube drawing

The process that typically requires a mandrel.

Core in casting

The function of a core in casting is to form internal cavities.

Tensile test

The test used in mechanical testing to measure ductility.

Annealing

The process of soaking a metal at high temperature and cooling it slowly.

Heat affected zone

The zone most susceptible to grain coarsening and thermal damage in welding.

Residual stress

Induced by nonuniform plastic deformation can be beneficial by improving fatigue resistance.

Hardenability of steel

Increased by alloying with chromium or molybdenum.

Shear deformation

The main mechanism of chip deformation in ductile materials.

Brazing

The joining process that operates entirely below the melting point of the base metals.

Thermal gradient

The process parameter most directly related to residual stress formation in additive manufacturing.

Time temperature transformation diagrams

Applicable to isothermal transformations.

Cold chamber processes

Typically used for aluminum and magnesium alloys in die casting.

Mechanical erosion

The mechanism responsible for material removal in abrasive jet machining.

Broaching vs. reaming

Broaching uses multiple cutting edges progressively.

Good corrosion resistance

A primary advantage of using aluminum.

High strength to weight ratio

Characteristic of titanium alloys.

Chverinov's rule

Helps estimate solidification time.

Aluminum

The most common metal used in die casting.

Springback

Elastic recovery of the material after it exits the roll in metal rolling.

Draft angle

Facilitates removal of the part of the mold in die casting and injection molding.

Strain hardening

Primarily occurs due to multiplication and entanglement of dislocations.

Modulus of elasticity

Calculated as the area under the elastic region of the stress-strain curve.

Engineering stress

Uses the original cross-sectional area.

Body centered cubic (BCC)

Materials with this structure have high strength and moderate ductility.

Invar

This nickel alloy has a near zero thermal expansion.

High carbon steels

Designated by a carbon percentage of >0.5%.

Covalent bonds

The primary type of bond with polymer molecules.

Penetration in casted products

Primarily caused by the metal being too runny.

Riser

The primary purpose is to provide extra metal for the mold.

Centrifuging

This type of centrifugal casting involves rotating the mold to distribute metal into thin, intricate cavities.

Permanent mold casting

NOT characterized by a slow cooling rate.

Hot working

Does not result in improved tolerances and dimensions.

Drawing

Typically used to form solid-bottom cylindrical containers from sheet metal.

Radial force

Present in oblique machining but not in orthonormal machining.

Conventional cuts in milling

Create initially thin chips with increasing strength.

Down milling

Occurs when the cutter rotation is the same as the direction of the feed rate.

Gang drilling

A type of drilling machine that uses multiple drill heads mounted on a single table to perform several operations simultaneously or in rapid succession.

Reaming

The most accurate method of making holes dimensionally.

Ultrasonic testing

The most effective non-destructive testing method at detecting delaminations in composite materials.

G28

The G-code command that tells the CNC to return home.

Continuous chips

Typically produced when machining ductile materials under low cutting speeds and high friction.

Resistance welding

Not characterized by low initial cost.

Swaging

A type of forging that uses external hammering to reduce the diameter or produce tapers or points.

Peening

Mechanical working of surfaces by repeated blows of impelled shot or a round-nose tool.

Shear forming

A modification of the spinning process.

Cutting tool geometry

Shank is not a real parameter.

Collet

The piece in a lathe used to hold parts with the least amount of run out.

Helium

A gas that can be used in plasma arc welding.

If the metal is too runny

Penetration in casted products is primarily caused by what?