The Effect of Repetitive Corrugation and Straightening by Rolling (RCSR)Process on the Semi-solid Microstructure of A356 Aluminum Alloy

Semi-solid metal forming is a new developing technology that has some advantages in relation to other forming and casting techniques. This process contains three main steps; feedstock manufacturing, reheating and forming. In this study, in order to produce highly strain feedstock from A356 aluminum alloy, a new severe plastic deformation method named repetitive corrugation and straightening by rolling (RCSR) is utilized. RCSR process including corrugated and flattened rollers acquires accumulative strain in material with minimum dimensional changes. A356 alloy specimens were subjected by RCSR process for various numbers of cycles to investigate the effect of strain on the morphology and shape factor of reheated specimens. Moreover, effect of holding temperature and time were on microstructure change were investigated. According to the microstructure observations, with increasing the number of RCSR cycles, besides decreasing in spherical size of particles, sphericity was increased and took place in less reheating time. Results indicate that RCSR process followed by reheating was effective to produce plate shape material with fine globular microstructure.

Keywords:

Semi-solid , RCSR , Aluminum alloy , Severe plastic deformation , Globular microstructure