The Effect of Al-5Ti-1B on Microstructure and Mechanical Properties of Al-12Si-xFe Alloy

Abstract

In present article, influence of grain refinement (Al5Ti1B) on the morphology of iron-rich β-phase intermetallic compounds in Al-12Si-Cu-Mg alloy having two addition levels of iron as alloying element has been reported. The mechanical properties such as tensile strength and ductility of base alloy and the grain refined alloys were measured. The effect of grain refiner on quality index of the alloys on the basis of mechanical properties was also assessed. It was observed that the higher iron content in an alloy results in coarser iron-rich β-phase intermetallic compounds in more quantity than low iron content alloy. The addition of grain refiner in an alloy modifies the distribution of iron-rich intermetallic compounds and changes their morphology from needle to blocky and Chinese script form besides reducing their average length and aspect ratio, which in turn improves the mechanical properties significantly. Further, it was observed that alloy with high iron (2.68 wt%) content required more quantity of grain refiner for better refinement and mechanical performance than the alloy with low iron content. Addition of grain refiner also increased the quality index of the low level iron alloy by about 50%, while that in case of high level iron alloy increased up to 136%.

Keywords:

• Aluminium
• Casting
• Grain refinement
• Mechanical properties
• Microstructure
• Quality

ACKNOWLEDGMENT

The authors wish to thank the National Council of Science and Technology (CONACyT) of México and the Department of Science and Technology (DST) of India (vide sanction letter DST/INT/Mex/RPO-07/2008 dated 08-12-2009), by financial support to Mexico-India bilateral project. Thanks to the UANL, Mexico, especially to María Lara Banda, for their support in carrying at the electron microscopy. Also thanks to technical staff: Julián Ramírez, Ricardo Leyva, and Ángle Gouzález. The authors gratefully thank Dr. Ezequiel A. Haro and Dr. Beatriz Luna for their continuous encouragement.