Assignment 2 Essay

Submitted By Haider-Haider
Words: 1324
Pages: 6

VBP263 Material Science: Review Questions # 3.

Please answers in your own words, NO CUT AND PASTE!
Use diagrams where appropriate.
All submissions to be typed in Font: Calibri, Size: 14.
Due: 24 Sept 2013, no late submissions accepted.
10 % of total assessment.

Name: Muhammad Noshad Student Number:4351655

Q1. What is an alloy? (2 Marks)
Q2. What is referred to as the phase of an alloy? (2 Marks)
Q3. What is phase equilibrium? (2 Marks)
Q4. Describe a phase diagram? (6 Marks)
Q5. What is a polymer? (2 Marks)
Q6. Define the difference between thermoplastic and thermosetting polymers? (4 Marks)
Q7. Describe what is meant by the Glass Transition temperature? (4 Marks)

Q1: What is an alloy?
Ans: An alloy is a mixture or solid solution compound of metals. An alloy will contain one or more of three: a solid solution of elements (a single phrase); a mixture of metallic phase (two phase or more); an intermetallaic compound with no distinct boundary between the phase. It is a mixture of metallic element with other metallic element or non-metallic element. Compound can also mixed to from ceramic materials.
Alloys are used in some applications as their properties are superior to those of the pure component elements for those applications.
Examples of alloys are solder, brass, pewter, phosphor bronze and amalgam.
Copper atoms are mixed with zinc atoms to form an alloy (brass).

Q2: What is refer to as a phase of an alloy?
Ans: A phase is a part of an alloy with uniform physical and chemical properties and the same composition. It is separated from their phases by a definite boundary on the phase diagram. e g snow and rain are the same substance, water, but because they have a different structure they are different phases and if they exist together, they have a definite boundary.

Q3: What is phase equilibrium?
Ans: Phase equilibrium is reached when, at a given temperature and pressure, there is no further tendency for change in characteristics of the phases, (microstructure or composition) with time.

Q4: Describe a phase diagram?
Ans: A phase diagram in physical chemistry, chemistry, mineralogy, and material science is a type is a type of chart is used to show conditioned at which thermodynamically distinct phases occur at equilibrium.
Common components of the phase diagram are lines equilibrium or phase boundaries, which refer to lines that mark condition under which multiple phases can coexist at equilibrium.

Phase diagram represent the relationship between temperature and composition of the phase present at the equilibrium.

An isomorphous system is one in the solid has the same structure for all compositions. The phase diagram shown is the diagram for Cu-Ni, which is an isomorphous alloy system.
Isomorphous system are not common, although there are number of isomorphous system is used. The copper-nickel system is an example.
In isomorphous systems the two components have unlimited solubility, which mean that they are like water and alcohol when they mix-they always form a solid solution regardless of the ratio of atoms/molecules.

Types of phase diagram

2D phase diagrams:
The simplest phase diagrams are pressure-temperature diagram of single simple substance, such as water. The axes correspond to the pressure and temperature. The phase diagram shows, in pressure temperature space, the line of equilibrium or phase boundaries between the three phases of solid, liquid and gases.

The typical phase diagram. The solid green line applies to most substances, the dotted green lines gives the anomalous behaviour of water. The green lines mark the freezing point and the blue line the boiling point, show how…