Precipitation of iron-rich intermetallics and mechanical properties of Al–Si–Mg–Fe alloys with Al–5Ti–B

ABSTRACT

Effects of added Al–5Ti–B master alloys on precipitation of iron-rich intermetallics and mechanical properties of A356 cast alloys with high Fe content (1.5 wt-%) were investigated using image analysis, scanning electron microscopy, and tensile testing. Results show that added Al–5Ti–B has apparent refinement on α (Al) grain size of A356 alloys that have high Fe content. 12 wt-% Al–5Ti–B is beneficial for improving mechanical properties of A356 cast alloys with high Fe content. Improved mechanical properties can be attributed to refined microstructure, the proper amounts of TiB₂ and Ti(AlSi)₃, and decreased porosity. An excessive amount of Al–5Ti–B deteriorates mechanical properties of alloys because it leads to the formation of large secondary intermetallics and increased porosity.

KEYWORDS:

• Al–Si cast alloys
• iron-rich intermetallics
• casting and solidification
• mechanical properties
• Al–5Ti–B master alloys

Acknowledgements

Special thanks to Ya Shi for his assistance in SEM observation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The financial support from the National Natural Science Foundation of China (51704084), China postdoctoral Science Foundation (2017M623068), Science and Technology Foundation of Gui Zhou Province of China [JC(2016)1026)], Young Talent Growth Foundation of Education Department of Gui Zhou Province of China[KY(2017)101)], Science and Technology Plan Project of Gui Zhou Province of China [RC2017(5788)].