Effects of Bi addition on Si features, tensile properties and wear resistance of hypereutectic Al-15Si alloy

Author(s)

Pereira, C. L. ; Gomes, L. F. ; Spinelli, J. E. ; IOP

• Document type: Journal article
• Source: 9TH WORLD CONGRESS ON COMPUTATIONAL MECHANICS AND 4TH ASIAN PACIFIC CONGRESS ON COMPUTATIONAL MECHANICS; v. 861, p. 8-pg., 2020-01-01.

Abstract

Al-Si alloys are very important in the automotive industry. This is thanks to their high strength to weight ratio, suitable fluidity, good corrosion resistance and high productivity. The shape of the eutectic Silicon (Si) has been widely studied since it is considered an index of quality regarding many application properties. Understanding the effects of alloy additions on the morphology of Si has drawn researcher's attention. One of these elements of interest is Bismuth (Bi), which may be part of the composition of Al-Si alloys either as an addictive or a contamination Hence, the microstructure aspects related to the presence of Bi are important requiring further consideration. In the present study, Al-15wt% Si hypereutectic alloy is modified with 1.0 wt% Bi. The goal is to compare the effect of this addition on the morphology of the phases forming the microstructure and on tensile/wear properties. In order to pursue that comparison, previously available data for the binary Al-15wt% Si alloy will be used. Various samples characterized by distinct cooling rates were generated by transient directional solidification of the ternary Al-Si-Bi alloy. The experimental variations of the eutectic spacing will be compared to each other based on their trends. It was found that the addition of minor Bi content (similar to 1%) permitted tensile strength and ductility of 195 MPa and 14%. Furthermore, wear resistance was improved thanks to Bi. The reasons for that will be outlined. (AU)

• FAPESP's process: 17/12741-6 - Application of experimental solidification techniques, characterization of microstructure and properties in the evaluation of eutectic and hypereutectic Al-base and Zn-base alloys
• Grantee: José Eduardo Spinelli
• Support Opportunities: Regular Research Grants