Properties

Question 1

What’s the gamma prime solvus of AD730?

Answer 1

1100C

Question 2

What’s the gamma prime solvus of Udimet 720?

Answer 2

1155C

Question 3

What is the gamma matrix typically made up from?

Answer 3

Nickel, Chromium, cobalt, rhenium, carbon, boron, molybdenum, Hafnium

Question 4

What is gamma prime typically made up from?

Answer 4

Ni3 (Ti,Al,Ta)

Question 5

What is gamma double prime typically made up from?

Answer 5

Ni3(Nb,Va)

Question 6

What is eta phase typically made up from?

Answer 6

Ni3 (Ti,Nb)

Question 7

What are the range of sizes for primary gamma prime?

Answer 7

1-10 microns

Question 8

What are the range of sizes for secondary gamma prime?

Answer 8

70-120 nm but can go to 225nm

Question 9

What are the range of sizes for tertiary gamma prime?

Answer 9

5-10nm after quenching

15-50 nm after ageing

Question 10

What is the definition of thermo-mechanical properties? Name a few

Answer 10

Properties you would only be able to determine through mechanical testing. 
Young’s modulus
Yield strength
UTS
poission’s ratio

Question 11

What is the definition of thermo-physical properties? Name a few

Answer 11

Properties only determinable through means not requiring work/mechanical testing
Thermo conductivity/resistivity
Diffusivity
Thermal expansion coefficient
Heat capacity

Question 12

What degree of misorientation is seen in low angle boundaries?

Answer 12

Less than 15 degrees

Question 13

What degree of misorientation is seen in high angle boundaries?

Answer 13

More than 15 degrees

Question 14

What role do grain boundaries play in affecting the strength of a material during plastic deformation?

Answer 14

Plastic deformation is mainly carried by dislocations. Grain boundaries act as sites for dislocation pileups preventing further movement of dislocations hence increasing the strength.

Question 15

Why do materials become stronger when strained/undergone work (work hardening)?

Answer 15

Plastic deformation is mainly carried by dislocations. Grain boundaries act as sites for dislocation pileups preventing further movement of dislocations hence increasing the strength.
Dislocations start blocking the movement of each other when there numbers increase.

Question 16

What impact do dislocations have on the mechanical properties of a material and why?

Answer 16

More dislocation increase the mechanical properties of the material.
A higher shear stress is needed to move the dislocations due to them blocking each other’s movement and due to dislocation pileup at the grain boundary.

Question 17

How is primary gamma prime formed?

Answer 17

From casting

Question 18

How is secondary gamma prime formed?

Answer 18

On cooling at high temps from SHT temp

Question 19

How is tertiary gamma prime formed?

Answer 19

Formed at low temps on cooling from SHT temp

Question 20

What is the difference between static and dynamic recovery?

Answer 20

If recovery occurs during deformation it is said to be dynamic

Question 21

What is the definition of recovery?

Answer 21

Deformed grains can reduce their stored energy by removal or rearrangement of defects/dislocations.

Question 22

What is the definition of recrystallisation?

Answer 22

Recrystallisation is the process by which deformed grains are replaced by new defect free grains which nucleate and grow until they consume the original grains entirely.

Question 23

What is Discontinuous dynamic recrystallisation?

Answer 23

Involves nucleation and grain growth at triple points and grain boundaries in metals with low stacking fault energies.

Question 24

What is continuous dynamic recrystallisation?

Answer 24

This is the transformation of subgrains into grains through the rotation of low angle sub grain boundaries

Question 25

What’s is geometric dynamic recrystallisation?

Answer 25

This is the evolution of the intial grains