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WorksheetsC5 Metal Strengthening Mechanism
Total questions: 15
Worksheet time: 7mins
When stress is applied and removed from a material of elastic...
Atoms displaced and diffuse to various positions.
Atoms spring back to original position.
Atoms stay at its last position.
Structure of atoms collapse.
Please choose the correct feature of the plastics deformation stages;
(a) Stress applied & elastic strain produced.
(d) Stress removed leaving permanent deformation.
(c) Stress applied & yielding occuring.
(b) No stress applied.
Plastic deformation occurs when large number of dislocations moves & multiply.
Yes
No
Why need to understand the relationship between dislocation motion & properties of material?
Ability of a metal to deform depend on the ability of dislocations to move.
The more constrained of dislocation motion, the easier metal to deform.
Restrict the dislocation motion make the metal more ductile.
Restrict the movement of dislocations make the material stronger & harder..
Pure aluminum is added with Si, Mg, Cu and Fe in different composition. The strengthening mechanism involved is?
Grain size reduction
Strain hardening
Solid solution strengthening
Hot work
Grain size can be controlled by?
Rate of solidification
Cutting process
Heat treatment
Do not know
What happen during strain hardening in metal?
Dislocations formed continue to move around.
Dislocations form & increased, by dislocation multiplications.
Dislocation-dislocation entangle to one another.
Distance between dislocations increased.
Effect of cold work process?
Decrease ductility of a metal.
Increased strength of metal.
Grain structure remain the same.
Produce higher internal stress.
Three stages of annealing process are;
Recrystallization
Grain growth
Grain size reduction
Recovery
Purpose of annealing process;
To increase strength of a metal.
To oppose dislocation motion.
Remove internal stress & process hardening to prevent cracking.
Reduce hardness & improve plasticity of a metal.
Recrystallization effect would depend on?
Environment
Time
Types of Materials
Temperature
What will happen during the recovery stage of an annealing process?
Reducing internal stress of grain boundaries.
Reduce strength & hardness of a metal.
The structure remain the same.
All the above.
What can you express about the figure?
Average grains decrease with time.
Direction of boundary movement & atomic motion is the same.
Grain growth of the structure.
Larger grains, grow by absorbing the small ones.
Disadvantages of hot working;
Poor surface finish.
Easier forming process.
Improve mechanical properties.
Materials loss to oxidation.
What can express about the figure?
Those are alloying elements in a metal.
1st stage of recrystallization stage.
Formation of new grains at grain boundaries.
Grow of new grains.
