MICROSTRUCTURAL STUDIES OF Ti-REFINED Al۲۰۱۴ ALLOY PREPARED BY SIMA PROCESS

In this study, Al۲۰۱۴ alloy refined with Al-۵%Ti-۱%B master alloy was prepared by strain-induced melt activated (SIMA) process. The main variables of the SIMA process were cold working, holding time and temperature in semi-solid state. Cold working was applied on specimens by upsetting technique to achieve ۱۰%, ۲۰% and ۳۰% height reduction. Cold worked specimens were heat treated in semi-solid state at ۵۸۵ °C, ۵۹۵ °C, ۶۰۵ °C, ۶۱۵ °C, ۶۲۵ °C and ۶۳۵ °C and were kept in these temperatures for different times (۲۰ and ۳۰ min). Observations through optical and scanning electron microscopy were used to study the microstructural evaluation. The results revealed that fine and globular microstructures are obtained by applying ۳۰ % height reduction percentage and heat treating in ۶۲۵ °C for ۳۰ min. Comparison between refined and unrefined Al۲۰۱۴ alloy after applying SIMA process showed that Al-۵%Ti-۱%B master alloy has no significant effect on average globule size but makes the final structure more globular.

Keywords:

Aluminum alloy , Grain refinement , SIMA process , Microstructure