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This blog will give you GUJARAT TECHNOLOGICAL UNIVERSITY Question paper of almost all subject.GTU is the university in Gujarat almost covered all the syllabus in Gujarat.GTU has given affiliation to 49 engineering colleges, 86 pharmacy colleges and 55 diploma institutes.

1         Tuesday 23 Feb. Formed a Project Team. The team’s focus is to investigate and test the properties of precipitation hardened 6000 series aluminium alloy pipe used in fabrication.

2         Alloy pipe from two sources – Australia and China- was obtained for comparison.

3         Initial counsel with mentor provided a format for testing and comparing pipe using ASTM testing methods.
Suggested procedure.

4         Conduct 3 point bend test

5         Measure deflection at yield= ductility comparison indicator.

6         Conduct hardness test.

7         From these 3 tests it was expected that a reliable comparison between the two sourced alloys could be made.

8         Research Background. Aluminium alloys are characterized by a relatively low density: (2.7 g/cm3) as compared with 7.9 g/cm3 for steel; high electrical and thermal conductivity and a resistance to corrosion in some common environments. Alloys are easily formed by virtue of high ductility and with an FCC crystal structure their ductility is retained even at very low temperatures. The chief limitation of aluminium is its low melting temperature (660C) which restricts the maximum temperature at which it may be used, and its low yield strength.
In comparison
Steel 1040 cold rolled       yield strength   490 Mpa      %EL  12
aluminium                           yield strength    34 Mpa       %EL  40

However, the strength and hardness of aluminium can be increased by alloying with these principle elements: copper, magnesium, zinc, manganese, iron ,chromium and silicon in small percentages; and solution heat treated in which all solute atoms are dissolved to form a single solid phase solution at @540C.
Cold working also strengthens these alloys.
But the maximum strength that can be obtained with an aluminium alloy is consequent to a process known as precipitation hardening, in which small particles of a secondary phase precipitate out of a cooled solid solution and thus reduce dislocation motion.
Precipitation hardening is achieved by two different heat treatments.
The first is a solution heat treatment in which all solute atoms of principle elements are dissolved to form a single-phase solid solution at @540C. At this point the alloy consists only of an alpha phase solid solution. This procedure is followed by rapid cooling or quenching to room temperature. This prevents the extent of any diffusion and the accompanying formation of precipitates. Thus a non-equilibrium situation exists in which only the single alpha phase solid solution supersaturated with principle element solute atoms is present at room temperature.
In this state the alloy is soft and weak similar to pure aluminium. Furthermore, diffusion rates of solute atoms at room temperature are extremely slow such that the single phase solid solution is retained at this temperature for relatively long periods.
For the second or precipitation heat treatment the supersaturated alpha solid solution is heated to a temperature @205C where diffusion rates become appreciable allowing beta phase particles to precipitate out of solution – a process known as artificial aging. The character of these beta phase particles, and subsequently the strength and hardness of the alloy depend on both the precipitation temperature and the ‘aging time’ at this temperature.
The dependence of the growth of precipitate beta particles on time and temperature can be represented from the data of tensile strength, yield strength or hardness at room temperature as a function of the logarithm of aging time at constant temperature.
With increasing time, the strength or hardness increases, reaches a maximum, and finally diminishes. This reduction in strength and hardness that occurs over long time periods is known as overaging. Most precipitation hardened alloys are limited in their maximum service temperatures. Exposure to temperatures at which aging occurs may lead to a loss of strength due to overaging. This is evidenced by microscopy which shows coarse particles (over precipitation) and large crystals.

9         Monday March 22   Conducted 3 point bend test on alloy pipe at Swinburne Engineering Laboratory- Hawthorn Campus.

10     Thursday May 13. Remet with mentor to show report thus far in group project.
Gained further advice to conduct the ‘second loop’ of the project.
This will be an overaging heat treatment on the alloy pipe followed by a 3 point bend test and hardness test.

11     Thursday May 13. Contacted Lab Technician and organized 3 point bend test to be conducted on overaged pipe on June 15.