It increases the dislocation density so that when dislocations interact subsequent deformation becomes more difficult. Dislocations may form dense'forests' or organise into cells.
2 of 15
How does thermo-mechanical processing control micro-structure?
Deforms it: creates dislocations,re-orientation. Heating it: relaxes and reorganises it
3 of 15
Name some common deformation techniques
Hot/Cold rolling (sheets), Extrusion (continuous cross section), Forging (discrete components)
4 of 15
Give advantages and disadvantages of Hot working(rolling)
Adv: increases ductility,porosity reduced(finer grains). Dis: Lost of strength
5 of 15
Give advantages and disadvantages of Cold working(rolling)
A physical property that has a different value when measured in different directions.
7 of 15
What does the term ' Texture' mean?
The amount of preferred orientation (how much the grains are orientated in the same direction)
8 of 15
How can deformation lead to texture?
Applying load on a material can cause the grain rotation creating a textures and elongated structure as each grain is affected by the surrounding grains.
9 of 15
Define necking
Necking is when large amounts of strain localises disproportionately in a small region of the material due to stress propagation.
10 of 15
Why do castings often show poor mechanical properties?
Castings can have heterogeneous grains size and shape; Castings often contain significant porosity
11 of 15
Which of the following would be observed on a stress vs. strain curve for a uniaxial tensile test, if the stress is released after loading to just below the yield point?
The plot shows zero strain
12 of 15
Work hardening of an alloy due to plastic deformation results in which of the following changes to its properties?
An increased yield stress
13 of 15
Which of the following processing routes would be most appropriate to produce a thin sheet with from a large cast block of aluminium alloy, while maximising the material's strength and providing a good surface finish?
Hot rolling followed by a final cold rolling pass.
14 of 15
Texture affects the properties of a solid metallic component because _________.
most crystals have anisotropic properties; processing of poly-crystalline materials affects orientation of its grains.
15 of 15
Other cards in this set
Card 2
Front
Why does deformation make a metal stronger?
Back
It increases the dislocation density so that when dislocations interact subsequent deformation becomes more difficult. Dislocations may form dense'forests' or organise into cells.
Card 3
Front
How does thermo-mechanical processing control micro-structure?
Back
Card 4
Front
Name some common deformation techniques
Back
Card 5
Front
Give advantages and disadvantages of Hot working(rolling)
Comments
No comments have yet been made