4 The Nature Of Materials And Solid-State Changes And Metals Flashcards
Materials having some degree of plasticity,relatively high hardness and strength,good electrical and thermal conductivity,crystalline when solids and opacity
Metals
A change of state from a solid directly to a gas is known as
Sublimation
Network groupings of identical unit cells that are aligned in parallel planes
Space Lattices
How many types of crystal lattice are there
14
Made up of nine atoms eight are located on the corners of the cube ninth position centrally between them
Box centered cubic lattice
Chromium, iron, molybdenum, tantalum, tungsten, and vanadium are examples of what lattice
Box centered cubic Lattice
Consists of 14 atoms with eight at the corners and the other six centered in the cubic face
Face centered cubic lattice
Aluminum, copper, gold, lead, nickel, platinum, and silver are examples of what lattice
Face centered cubic lattice
Consist of 17 atoms,seven atoms are located in each hexagon face with one at each corner and the seventh in the center
Hexagon Close Packed Lattice
Cadmium, cobalt, magnesium, titanium, and zinc are examples of what Lattice
Hexagon close-packed Lattice
Missed placed atoms are in layers about the grains are known as
Grain boundaries
Deformation of metallic crystals occurs in three ways
Slip, twinning, and rotational deformation
Occurs by translation or sliding between the atomic planes within a grain
Slip Deformation
Grains deform by twisting or re-orientating a band of adjacent lattice forms with each unit cell remaining in contact with the same neighbor it had before deformation
Twinning Deformation
A shift in the grains of rotational deformation of portions of the crystal lattice
Rotational Deformation
After a large percentage of grains have been reorientated by action of considerable deformation work, the metal is likely to take on a directional properties called
Fibering
Work accomplished below the recrystallization temperatures for the particular material
Cold work
Electrical properties and corrosion resistance are improved and residual stress are reduced during what process
Stress Relief (Recovery)
Recovery of ductility to permit further change of shape by deformation can be obtained only by elimination of the deformation grains, and this is accomplished by
Recrystallization
Recrystallization at a higher temperatures is sometimes also called stress relieving. The same process may be referred to as
Process Annealing
If fine grain structures is desired after the recrystallization process, it is necessary to reduce the temperature quickly to prevent subsequent grain growth. This is usually performed by some kind of
Quench
Metal alloys that display a variable solid-state solubility of one metal in another with change of temperature may be susceptible to
Age hardening
One of the greatest uses of precipitation hardening is for improvement of properties of some
Aluminum alloys
NDT methods capable of indicating changes in electrical conductivity and to some extent can provide absolute measures of electrical conductivity
Eddy Current and Thermo electric methods
When steel is heated to or above the critical temperature, the value of which is dependent upon the alloy percentages, and held at temperatures for some period of time, carbon unites in a solid solution with iron in the gamma or face centered cubic lattice form is known as
Austenitizstion
The heat treating process for softening and regaining ductility in connection with cold working a material is known as
Annealing
When steel is not reduce to it softest condition and the pearlite is left rather fine instead of course is known as
Normalizing
Minimum hardness and maximum ductility of steel can be produced by a process called
Spheroidizing
NDT surface examinations that can detect cracks by either heating or quenching are
MT PT ET
Consist of quenching an austenitized steel in a salt bath at a temperature about that needed for the start of martensite formation is known as
Martempering
When steel is held at the bath temperature for a longer period and the results of the isothermal treatment is the formation of bainite this is known as
Austempering
Steel that has been hardened by heat treatment and then stress relieved, softened, and provided with increased ductility by reheating is known as
Tempering or Drawing
Deterioration of metals by the chemical action of some surrounding or contracting medium which may be liquid, gas, or some combination of the two is known as
Corrosion
Technique used to detect and record the progression of cracking due to stress corrosion is known as
Acoustic Emissions
A localized corrosion by which pits that extend deep into the metal develop
Pitting
A serious type of corrosion is created when the attack is against the grain boundaries is known as
Intercrystalline Corrosion
Technique that is particularly effective in detection and accurate measurement of overall thinning that results from corrosion
Ultrasonic
Commonly applied to detect corrosion and corrosion thinning in interior and otherwise inaccessible regions of assemblies, insulated components, and the like
Radiography
Used to monitor the initiation and growth of stress corrosion and hydrogen embrittlement cracks
Acoustic Emissions
