Phase diagrams; quench / temper / anneal; superalloys; high-entropy alloys; grain boundaries; dislocation plasticity; precipitation hardening; metallography; CMC / MMC composites.
Metallurgy and Alloys
Phase diagrams (iron-carbon)
Fe-Fe3C diagram (Roozeboom 1900): austenite, ferrite, cementite, pearlite, ledeburite phases; eutectoid point at 727 C and 0.76 wt percent…
Quench-temper (martensite)
Rapid cooling traps carbon in BCT martensite (very hard, brittle); subsequent tempering 200-700 C precipitates carbides and restores…
Superalloy (nickel-based)
Ni-base superalloys (Inconel, Rene N5, CMSX-4) gamma-prime Ni3(Al,Ti) precipitates in gamma matrix; single-crystal turbine blades operate…
High-entropy alloys (metallurgy)
Yeh / Cantor 2004: 5-plus elements in equimolar ratios stabilize single-phase solid-solution via configurational entropy; e.g. CoCrFeMnNi…
Grain-boundary strengthening (Hall-Petch)
Hall-Petch 1951: yield strength sigma_y = sigma_0 + k_y / sqrt(d), where d is grain size; nano-grain materials achieve very high strength…
Dislocation plasticity (Orowan)
Orowan 1934 plastic flow via dislocation glide; Taylor relation tau = alpha G b sqrt(rho); slip systems determine ductility; FCC has 12…
Precipitation hardening
Wilm 1906 Duralumin (Al-Cu age-hardening); GP zones nucleate to coherent intermediate phases to incoherent equilibrium phase; Orowan…
Metallic bonding (electron sea)
Drude-Sommerfeld free-electron model; delocalized valence electrons explain conductivity, ductility, opacity, luster; tight-binding refines…
Steel classification (AISI / SAE)
AISI-SAE 4-digit grade: 10xx plain-carbon, 41xx Cr-Mo, 43xx Ni-Cr-Mo, 304 / 316 austenitic stainless; ASTM, EN, JIS parallel naming systems…
Metallography (etching / SEM / EBSD)
Nital, picral, Keller etchants reveal microstructure under optical microscopy; SEM/BSE shows phases; EBSD maps grain orientations and…
Recrystallization and annealing
Cold-worked metal stores ~10 percent of plastic-work as defects; on annealing, recovery (point-defect annihilation) then recrystallization…
CMC and MMC composites
MMC (metal-matrix) e.g. Al-SiC for aerospace and brake-rotors; CMC (ceramic-matrix) e.g. SiC/SiC for turbine and nuclear-cladding (GE LEAP…
Amorphous metal + glass transition
Bulk metallic glasses (BMG) form when cooling rate exceeds critical R_c: Vitreloy-1 R_c ~1 K/s allows mm-thick samples; glass transition…
Welding + heat-affected zone
Fusion welding creates rapid heat cycle: T peaks above T_m at fusion-zone, T_g < T_peak < T_m in HAZ; grain growth + carbide precipitation…
Fatigue (S-N curve / Coffin-Manson)
Wohler S-N curve: fatigue-life N_f decreases as cyclic-stress amplitude S increases; Basquin power-law S = sigma_f' (2 N_f)^b;…
Creep + Larson-Miller parameter
High-T deformation under constant stress: primary + secondary (steady-state Norton power-law epsilon_dot = A sigma^n exp(-Q/RT)) +…
Oxidation (Pilling-Bedworth ratio)
Pilling-Bedworth 1923 ratio PBR = V_oxide / V_metal: PBR < 1 (Mg, Ca) porous non-protective; 1 < PBR < 2 (Al, Cr, Si) protective adherent;…
Intermetallic compound (Laves phase)
Laves 1936 AB2 close-packed intermetallic phases (MgZn2, MgCu2, MgNi2 prototypes); strengthen Ni-superalloys + Ti-Al via gamma'/Laves…
Bain (1928)
E Bain 1928 + 1962 'Functions of Alloying Elements in Steel'; modern modern foundational text + TTT-diagram + 2024 modern dual-phase-steel…
Hume-Rothery rules (1925)
W Hume-Rothery 1925 size + valence + electronegativity; modern modern foundational text + Goldschmidt + 2024 high-throughput alloy ML.
Pauling metals (1948)
L Pauling 1948 'Resonating-valence-bond theory of metals'; modern modern foundational text + 2024 high-Tc and metallic-bond…
Hall-Petch (1951)
E Hall 1951-N Petch 1953 σ_y = σ_0 + k/√d grain-size strengthening; modern modern foundational text + nano-grain breakdown 2024…
HEA (Yeh-Cantor 2004)
J-W Yeh-B Cantor 2004 high-entropy-alloy; modern modern foundational + CrCoNi 2024 NSCM + 2024 ML-driven-discovery 100k composition…
Nitinol (Buehler 1962)
W Buehler 1962 NiTi shape-memory; modern modern foundational text + bio-medical-stent + 2024 4D-printing shape-memory-biomedical.