Chapter 7 - Dislocations & Strengthening Mechanisms

Flashcards covering key concepts and terms from Chapter 7 on dislocations and strengthening mechanisms in metals.

dislocations

Plastic deformation occurs by motion of __.

In metals, dislocation motion is relatively easy due to _______.

metalic bonding

A __ dislocation moves parallel to the applied shear stress.

edge

A dislocation that moves perpendicular to the applied shear stress.

screw

For FCC crystal structures, there are a total of __ independent slip systems.

12

The strength and hardness of metals are related to the __ of dislocations.

mobility

Name the three mechanisms for strengthening metals:

grain size reduction, solid solution strengthening, and strain hardening.

barriers

Grain boundaries act as __ to dislocation motion.

During recrystallization, new grains form that have low dislocation __.

densities

Recovery, recrystallization, and grain growth are processes involved in __ of deformed metal specimens.

heat treatment

After cold working, metals generally become __ and stronger.

harder

When a dislocation is blocked, it cannot __.

move

In single metals, slip occurs on a specific __ system.

slip

Heat treating of cold-worked metals can decrease tensile strength and increase __.

ductility

The yield strength of single crystals depends on the critical resolved ________.

shear stress

As the dislocation density increases with deformation, the space between dislocations __.

decreases

The __ of metals influences their mechanical properties.

grain size

A __ treatment is sometimes used to relieve effects of cold work of metals.

heat

Caterpillar locomotion is an analogy for __ motion.

dislocation

_ requires higher shear stress due to tensile strains around dislocations.

Solid solution strengthening

Tensile strength increasing with higher concentrations of an alloying element (like Ni) illustrates __.

solid-solution strengthening