4.2a Metals and Metallic Alloys Flashcards
What is the distribution of metal?
Not evenly distributed and rarely found in pure deposits. They are typically found combines with other elements in localized areas
What is ore?
Rocks that contain metals that can be extracted
What characteristics define the metal extraction process?
Complex
Energy intensive
Environment, economic + social implications
What is the structure of a metal?
Metals are crystalline structures made up of grains
What are the properties of small grains?
Low tensile strength
Low toughness
Low ductility
High brittleness
What are the properties of large grains?
High tensile strength
High toughness
High ductility
High malleability
What influences the grain size?
The type of heat received while cooling
Rapid cooling (small grains)
Slow cooling (large grains)
What are the ways of modifying physical properties of metals?
Alloying
Work Hardening
Tempering
What are alloys and the impact on physical properties?
The mixture of one metal with another metal/ non-metal
Material has unique properties including:
Increased hardness and strength
Reduced malleability and ductility
What is work hardening?
The process of increasing the hardness of a metal by applying a treatment when the metal is cold
What is tempering and the impact on physical properties?
The application of heat after work hardening
Reduces the hardness and stiffness
Increased toughness and ductility
What are super alloys?
Metal alloys that exhibit high degrees of mechanical strength, resistance to corrosion, and surface stability
What do super alloys have a high resistance to?
Creep: the slow expansion or deformation of a material over time
Oxidation: the reaction of a metal with oxygen
What is the recovery and disposal process for metals and metallic alloys?
Easy and indefinitely recyclable
Use less energy/ produce less waste
What categories are metals/ metallic alloys categorized into?
Ferrous alloys (contain iron + magnetic)
Non-ferrous alloys (do not contain iron)
