04 Metals and Alloys Free Online FlashCards

What is an alloy?

An alloy is a metallic material made from a metal and one or more additional elements.

How can crystal structure affect a metal's ductility?

Crystal structure influences how readily a metal deforms; the arrangement and availability of slip systems help determine its ductility.

What crystal structure does iron have at room temperature?

Iron has a body-centered cubic (BCC) structure at room temperature.

How do substitutional and interstitial solid solutions differ?

In a substitutional solid solution, alloy atoms replace host atoms; in an interstitial solid solution, they fit into spaces between host atoms.

What moves through a metal crystal during plastic deformation?

Plastic deformation in metals occurs mainly as dislocations move through the crystal.

How does work hardening change a metal?

Plastic deformation raises dislocation density; the dislocations obstruct one another, increasing strength and hardness while usually reducing ductility.

How does solid-solution strengthening work?

Dissolved alloy atoms distort the crystal lattice and impede dislocation motion, strengthening the metal.

What are common effects of annealing?

Annealing commonly softens metal, relieves stresses, and improves ductility or formability.

Why is quenched steel often tempered?

Quenching can form hard martensite in steel. Reheating to a lower temperature during tempering reduces brittleness and improves toughness while retaining useful strength.

How does solution treatment and aging strengthen many aluminum alloys?

Solution treatment dissolves alloying elements into a solid solution. Cooling retains a supersaturated solution, and later aging forms fine strengthening precipitates.

Which crystal structure do aluminum and copper share?

Aluminum and copper have face-centered cubic (FCC) crystal structures.

What crystal structure does magnesium have?

Magnesium has a hexagonal close-packed (HCP) crystal structure.