Properties Flashcards
What’s the gamma prime solvus of AD730?
1100C
What’s the gamma prime solvus of Udimet 720?
1155C
What is the gamma matrix typically made up from?
Nickel, Chromium, cobalt, rhenium, carbon, boron, molybdenum, Hafnium
What is gamma prime typically made up from?
Ni3 (Ti,Al,Ta)
What is gamma double prime typically made up from?
Ni3(Nb,Va)
What is eta phase typically made up from?
Ni3 (Ti,Nb)
What are the range of sizes for primary gamma prime?
1-10 microns
What are the range of sizes for secondary gamma prime?
70-120 nm but can go to 225nm
What are the range of sizes for tertiary gamma prime?
5-10nm after quenching
15-50 nm after ageing
What is the definition of thermo-mechanical properties? Name a few
Properties you would only be able to determine through mechanical testing. Young’s modulus Yield strength UTS poission’s ratio
What is the definition of thermo-physical properties? Name a few
Properties only determinable through means not requiring work/mechanical testing Thermo conductivity/resistivity Diffusivity Thermal expansion coefficient Heat capacity
What degree of misorientation is seen in low angle boundaries?
Less than 15 degrees
What degree of misorientation is seen in high angle boundaries?
More than 15 degrees
What role do grain boundaries play in affecting the strength of a material during plastic deformation?
Plastic deformation is mainly carried by dislocations. Grain boundaries act as sites for dislocation pileups preventing further movement of dislocations hence increasing the strength.
Why do materials become stronger when strained/undergone work (work hardening)?
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.
What impact do dislocations have on the mechanical properties of a material and why?
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.
How is primary gamma prime formed?
From casting
How is secondary gamma prime formed?
On cooling at high temps from SHT temp
How is tertiary gamma prime formed?
Formed at low temps on cooling from SHT temp
What is the difference between static and dynamic recovery?
If recovery occurs during deformation it is said to be dynamic
What is the definition of recovery?
Deformed grains can reduce their stored energy by removal or rearrangement of defects/dislocations.
What is the definition of recrystallisation?
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.
What is Discontinuous dynamic recrystallisation?
Involves nucleation and grain growth at triple points and grain boundaries in metals with low stacking fault energies.
What is continuous dynamic recrystallisation?
This is the transformation of subgrains into grains through the rotation of low angle sub grain boundaries
What’s is geometric dynamic recrystallisation?
This is the evolution of the intial grains
