Chapter 9 Phase diagrams Flashcards
solution and mixture
Mixtures are materials that contain two or more chemical substances dispersed among each other (mixed together). … Solutions are homogenous mixtures: particles of one substance (the solute) are mixed together with the particles of another substance (the solvent) – eg salty water.
solubility limit
components and phases in an aluminum-copper alloy
Components: The elements or compounds which are present in the alloy (e.g., AI and Cu)
Phases: The physically and chemically distinct material regions that form
effect of temperature and composition
criteria for solid solubility
A simple system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed in its functioning
phase diagrams
Phase diagrams represent the relationship between temperature and the composition of phases present at equilibrium
What is an isomorphous binary phase diagram?
What is an isomorphous binary phase diagram?
Typically, the isomorphous system has a liquid area, a solid area, and an area that is a mixture of both liquid and solid. Typically, a binary isomorphous phase diagram consists of two phase boundaries: the liquidus and the solidus.
phase diagrams
determination of phases
Rule 1
phase diagrams
determination of phases
Rule 2
phase diagrams
determination of phases
Rule 3
the lever rule
the lever rule is a formula used to determine the mole fraction (xi) or the mass fraction (wi) of each phase of a binary equilibrium phase diagram.
Ex.
cooling of a Cu-Ni alloy
cored vs equilibrium structures
Mechanical Properties: Cu-Ni System
binary eutectic systems
eutectic systems
microstructural developments in eutectic systems
part 1
microstructural developments in eutectic systems
part 2
microstructural developments in eutectic systems
part 3
microstructural developments in eutectic systems
part 4
hypoeutectic vs hypereutectic
If an alloy is not of eutectic composition then it is either hypereutectic or hypoeutectic. If the alloys’ composition places it to the left of the eutectic point on a phase diagram, then it is hypoeutectic. If it is to the right of the eutectic point then it is called hypereutectic.
intermetallic compounds
An intermetallic is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elements. Intermetallics are generally hard and brittle, with good high-temperature mechanical properties.
Eutectic - liquid ________________ phases
Eutectoid — one _______________ to two other solid phases
Peritectic - liquid ______________________ to a second solid phase heat
eutectoid and peritectic
phase diagrams
iron-carbon phase diagram
hypoeutectoid steel
hypereutectoid steel
alloying with other elements
Summary
Phase diagrams are useful tools to determine ___________________________
The microstructure of an alloy depends on _____________________________
Important phase diagram phase transformations include ____________________________
