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HPAM Paul 1 - Coggle Diagram

- - - - Faceted growth determined by ratio of entropies of fusion >2
      - Entropy of fusion = Latent heat / melting temp
  - - - Coarser structures formed with bad effect on mech properties
  - - - :arrow_up: cooling rate
      - Chemical modification using Na and Sr
  - - - Absorbed into interface forcing Si to twin, twin then facets
    - - AlNaSi phase nucleates Si
      - Al2Si2Sr depletes melt of Sr
  - - - Forms intermetallic phases that grow as large plates
      - Large plates are brittle under stress = poor ducility
- - - - Primary Al (cleanliness and control of elements)
      - Substantial post casting processign
      - Investment and sand cast
      - Higher profit
      - Inspection quality assurance
    - - Recycled Al (higher impurity tolerated)
      - Lower profit
      - Lean processes (natural age hardening)
      - Die and sand cast
      - Design quality assurance
  - - - Al-Ti peritectic forms \(Al_3Ti\)
      - Most effective when Ti > peritectic composition
      - Added as Al-Ti master alloys
      - Rapid dissolution into hypo-peritectic alloys
      - Multiple orientation relationships observed between \(Al_3Ti\) and Al = more grain nucleation
    - - Pre-existing nuclei
      - Added in rod form before casting
      - Epitaxial relationship - match up for good nucleation
      - Nucleation occurs on largest TiB2 particles
      - :check: Long lived effect
        thermodynamically stable
        TiB2 formed in situ
        No undercooling required to nucleate Al phase
        (Undercooling is bad, settling out material)
    - - Solute enriched layer ahead of solidification front
      - Temp gradient in liquid > Solutal liquidus temp = stable interface
      - Temp gradient in liquid < Solutal liquidus temp = unstable interface
        
        Rapid dendritic growth = Breakdown in grain refining effect
    - - Improved feeding
        Improved x-ray and US resolution
        Increased resistance to hot tearing
        Improved mech properties
        Improved fatigue resistance
        Improved resistance to grain boundary corrosion
        Improved hot forming
- - - - Carry engines and fuel
      - Experience both tension and compression and forces alternate
      - Upper
        
        High modulus
        
        High compressive strength
        
        SCC resistance
        
        Fatigue resistance
      - Lower
        
        High modulus
        
        High TS
        
        Damage tolerance
        
        Fatigue resistance
    - - A tube in 3 point bending
      - Upper
        
        SCC resistance
        
        High tensile yield stress
        
        High modulus
        
        Low density
        
        Fatigue resistance
      - Lower
        
        Impact resistance
        
        High compressive yield stress
        
        High modulus
        
        Low density
        
        Fatigue resistance
    - - Parasitic (occupies space) so must be compact
      - Large impact forces
      - Corrosion protection
      - Steel: Clean melted, VAR and electric arc refined so inclusions no bigger than 0.05um
    - - Slats and flaps, rudder and ailerons, spoilers - all modify airflow
      - Low inertia (low mass)
      - High stiffness
  - - - Stiffener
        
        \(E/\rho\)
    - - Landing gear
        
        \(E/\rho^2\)
    - - Skin, Surface control
        
        \(E/\rho^3\)
- - - - coherent with FCC matrix, small mismatch gives spherical precipitates, coherent up to 180nm
    - - Incoherent spherical particles to block persistant slip bands
      - Develop during deformation of \(\delta'\) strengthened alloys
      - T1 phase is similar but less effective as forms as larger plates
      - Form on grain boundaries but forming through bulk is better at preventing slip band formation
        
        Alloy is cold worked to :arrow_up: dislocation density which acts as nucleation sites to refine distribution of S phase, :arrow_up: max fatigue stress