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PM Moataz Nickel 1 - Coggle Diagram

- - - - Grain size banding, Precipitate banding, presence of bands
  - - - Channel type enriched in gamma prime and carbide forming elements
      - Made by gravity driven flow of lower density interdendritic fluid to carve out a channel
      - Seen as a spot in cross section or line in longitudinal section
      - :forbidden: Highly segregated and brittle
      - :check: Avoid deep melt pools in VAR
    - - Periodic variation of grain size across diameter
      - Short term variation in the VAR melt rates
    - - Refractory oxides from VIM
      - Quantity and size can be diminished by VAR remelting
      - ESR significantly reduces size and quantity
      - Ultrasonic detected
    - - Isolated spots of no precipitate with large grain size
      - Drop in type defect from electrode denuded in gamma prime elements. Can be dirty or clean
      - Impact: :green_cross:Clean = weaker material, tolerated if small
        :forbidden:Dirty = Lots of inclusions and very bad
      - :check: Don't remelt pipe, maintain stable VAR conditions, rigorous mould cleaning between melts
- - - - Vacuum melting:
        
        Prevented loss of reactive constituents
        
        :arrow_up: concentrations of Ti and Al for creep resistance
        
        Greater consistency of mech properties
    - - First alloy to be cast
      - Al+Ti improved creep, but increased density. Also had low ductility
    - - Removal of transverse grain boundaries :arrow_up: stress rupture strength and thermal fatigue resistance
      - Columnar grains
    - - No grain boundaries means no need for boundary strengthening elements
        
        Increase in meltig temp from 25C to 50C
        
        Allowed solution treating at higher temps
        
        Larger volume fraction of gamma precipitate
      - Good properties in both transverse and longitudinal
    - - Used to develop final microstructure but can introduce residual stresses