کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
830182 | 1470351 | 2013 | 9 صفحه PDF | دانلود رایگان |
The effects of strain induced melt activated (SIMA) process parameters on the microstructure evolution of an A356 aluminum alloy have been investigated. It is concluded that a fine uniform globular microstructure may be obtained through heating the 45% pre-deformed specimen at 615 °C for 6 min. In addition, a model for microstructure evolution during SIMA process is proposed. This accounts for the mechanisms causing the microstructural changes in two successive steps of pre-deformation and heating. The present work also explores the semi-solid deformation behavior of the experimental alloy possessing different initial microstructures, including cast, rosette-like, globular and coarsened ones. The applied thixoforming process encompasses a set of isothermal hot compression tests in the semi-solid temperature range. The results indicate that the SIMA processed specimen with globular microstructure exhibits the lowest flow resistance during thixoforming process, followed by those with coarsened, rosette-like and cast microstructures. This has been justified considering the governing deformation mechanisms for different thixoformed microstructures.
► A proper globular microstructure was obtained after 45% strain and holding at 615 °C for 6 min.
► Ostwald ripening was the dominant coarsening mechanism for SIMA processed A356 alloy.
► A model for microstructure evolution of A356 aluminum alloy during SIMA was proposed.
► The effect of initial microstructure on the semi-solid deformation behavior was studied.
Journal: Materials & Design - Volume 46, April 2013, Pages 579–587