Assessment of Thermal Cycling Creep Lifetime of Al-Si Alloys

摘要

Thermal cycling creep lifetime of Al-Si cast alloys was estimated in experimental ways. Thermal cycling creep tests on the samples of AlSi7 and AlSi18 alloys in different solution treatment conditions were conducted in the temperature range of 50～300℃. Stress exponents of AlSi7 and AlSi18 alloys were computed and found to be in the range of 4.4～5.2 and 2.0～3.1 according to the solution treatment conditions, respectively. Mathematical model for prediction of thermal cycling creep lifetime of the alloys was proposed on the base of conservation of strain energy during the creep process. The theoretical predictions were compared with the ones of the experiment results, and good agreement was obtained. Metallography pictures of the tested materials have been taken to check the influence of microstructures on the creep resistance and ductility of the materials.