MATEPRO Module 4 Flashcards
In material selection, These materials were selected primarily because, not only did
they possess the desired properties and characteristics for
the intended functions of specific parts, but also they were
the ones that could be manufactured at the _________ cost
Lowest
With regards to the structures of materials, the ____________ and _____________ of a material all boil down to its ______________ and _____________.
Properties and performance, structure and processing
The number of protons in the nucleus
determines whether an atom will be
____________, ______________, or _______________
(low, high, intermediate)
Metallic, nonmetallic, or semimetallic.
Combination of multiple atoms
Molecules
Attractive Forces that hold the molecules together
Bonds
Examples of primary bonds are _________, ____________, _____________
Ionic bonds, Covalent Bonds, Metallic Bonds
Secondary bonds include _____________.
van de Waals forces
Occurs when one or more electrons from an outer orbit are transferred from one atom to another.
Ionic bonds
Ionic bonds generally have ____________ and ________________.
Poor ductility and low thermal/electrical conductivity.
The electrons in outer orbits are shared by atoms to form molecules. Atoms achieve stability by sharing electrons with other atoms
Covalent Bonds
Covalent bonds generally have ____________, ____________, and ________________.
Low electrical conductivity and high hardness, and high melting point.
Occurs in atoms with very few valence electrons (1-3)
Metallic bonds
Metallic bonds generally have ____________ and ________________.
High thermal and electrical conductivity.
Occurs when a molecule is polarized: one side is more positive/negative than the other. The attraction of opposite charges without electron transfer
Van der Waals forces
The various orderly configurations of the atoms when metals solidify from a molten state
Crystals
Refers to the atomic arrangement when solidified
Crystal Structure
The smallest group of atoms showing the characteristic
lattice structure of a particular metal. It is the building block of
crystal.
Unit Cell
Topologically ordered, three-dimensional geometrical array of atoms composed of one or more repeating unit cells
Lattice Structure
Lacks the periodically ordered arrangement
that is characteristic of a crystalline solid
Amorphous Structure
When metals solidify, the atoms assume a _______________.
Crystal Structure
A metal is normally made up of only____-______ or ______________
structure, but some can have multiple. These are called _____________ or ____________.
One crystal structure or lattice structure, allotropic or polymorphic
For the crystal structure of metals, three basic atomic arrangements include the following (mention their characteristic)
- Body-centered cubic (BCC); high strength
- Face-centered cubic (FCC) ; high ductility
- Hexagonal Close Packed (HCP); Brittle
The change of a metal’s
lattice structure from one form to another
Allotropic transformation
The top and bottom planes in the HCP structure
Basal Planes
