Alloys, B390, A380, and Al-Ni, used had the following compositions; Al-17Si-4Cu-0.5Mg, Al-8.5Si-3Cu-1.3Fe-0, and Al-14Si-4Cu-2Ni-1Fe respectively. Among A380, Al-Ni alloys, and B390 alloy, the Al-Ni alloy showed the greatest creep resistance [Bob Schmitz].

51K alloy and A380 alloy showed no substantial difference between the relaxation in compression versus relaxation in tension. Bolt load: after one week at operating temperature the engine bolts tested at 220C lost an average of 70% of the initial preload. Engine compliance entails a condition intermediate between creep and relaxation. [Sonny N.]

Creep and stress relaxation were studied for one eutectic and two hyper-eutectic Al-Si alloys. Eutectic Al-Si alloy had the best creep resistance (lowest amount of strain for a given time) and the longest rupture times. Activation energies of the eutectic alloy increased, nearly linearly, with stress [Tim Jaglinski].

M4032-2 exhibits better creep performance than 51 K as well as eutectic alloy. Briggs & Stratton M4032-2 alloy and Harley-Davidson 332 aluminum alloy exhibit similar creep with M4032-2 offering somewhat better performance. Recovery is incomplete, particularly at the higher stresses and temperatures. [Jay Dandrea].