Non Ferrous alloys MSE 528

Mg alloys for automotive

Copper and its Alloys

Beta stabilizer

Ti alloy Alpha stabilizers: C, O, N and Al Beta Stabilizers: Cr, Fe, Pd, Co, Mn, H, V, Mo, Ta, Nb Alpha alloys: Ti-5Al-2.5Sn, Ti-4al-1Mo Beta alloys: Beta 21S (13%Mo), Alpha + Beta alloys: Ti-6Al-4V, ELI: extra low level Interstitials

TixAl

20 Particles impede dislocations. Ex: Al-Cu system Procedure: --Pt A: solution heat treat (get  solid solution) --Pt B: quench to room temp. --Pt C: reheat to nucleate small  crystals within  crystals. Other precipitation systems: Cu-Be Cu-Sn Mg-Al Adapted from Fig , Callister 6e. (Fig adapted from J.L. Murray, International Metals Review 30, p.5, 1985.) Adapted from Fig , Callister 6e. PRECIPITATION HARDENING

Al Alloy: TS peaks with precipitation time. Increasing T accelerates process. %EL reaches minimum with precipitation time. Adapted from Fig (a) and (b), Callister 6e. (Fig adapted from Metals Handbook: Properties and Selection: Nonferrous Alloys and Pure Metals, Vol. 2, 9th ed., H. Baker (Managing Ed.), American Society for Metals, p. 41.) PRECIPITATE EFFECT ON TS, %EL

24 Hard precipitates are difficult to shear. Ex: Ceramics in metals (SiC in Iron or Aluminum). Result: PRECIPITATION STRENGTHENING

26 Internal wing structure on Boeing 767 Aluminum is strengthened with precipitates formed by alloying. Adapted from Fig , Callister 6e. (Fig is courtesy of G.H. Narayanan and A.G. Miller, Boeing Commercial Airplane Company.) Adapted from Fig. 11.0, Callister 5e. (Fig is courtesy of G.H. Narayanan and A.G. Miller, Boeing Commercial Airplane Company.) 1.5  m APPLICATION: PRECIPITATION STRENGTHENING