Refinement effect of two rare earth borides in an Al-7Si-4Cu alloy: A comparative study
- School of Materials Science and Engineering, Jiangsu Key Laboratory of Advanced Metallic Materials, Southeast University, Nanjing 211189 (China)
Highlights: • Refinement performance of Al-La-B and Al-Ce-B refiners in Al-7Si-4Cu alloy was investigated. Due to the orientation relationships between rare earth borides and Al, CeB{sub 6} and LaB{sub 6} can act as the nucleation substrate of α-Al and refine Al-Si-Cu casting alloy effectively. • Al-Ce-B refiner showed better refining efficacy than Al-La-B refiner because of the lower lattice mismatch and less angel difference of the certain orientation relationship between CeB{sub 6} and Al, demonstrated by TEM analysis. • Effects of Al-La-B and Al-Ce-B refiners on alloy defects and tensile properties were investigated. The best refiner addition level in this alloy is considered to be 1.0wt%. Tensile properties of Al-7Si-4Cu alloy were prominently improved owing to the better refined microstructures and much fewer shrinkage defects. - Abstract: In this paper, refinement performance of Al-La-B and Al-Ce-B refiners in Al-7Si-4Cu alloy and their effects on alloy defects and tensile properties were investigated. Due to the orientation relationships between rare earth borides and Al, CeB{sub 6} and LaB{sub 6} can act as the nucleation substrate of α-Al and refine Al-Si-Cu casting alloy effectively. Al-Ce-B refiner showed better refining efficacy than Al-La-B refiner because of the lower lattice mismatch and less angel difference of the certain orientation relationship between CeB{sub 6} and Al, demonstrated by TEM analysis. Tensile properties of Al-7Si-4Cu alloy were prominently improved from 204.4 ± 5.9 MPa to 250.6 ± 6.7 MPa in as-cast state and 335.7 ± 6.5 MPa to 386.0 ± 7.0 MPa in heat treatment state owing to the better refined microstructures and much fewer shrinkage defects. However, when the addition level of the refiners was higher than 1.0 wt%, the amount of gas pores in the alloy significantly increased. Hence, the best refiner addition level in this alloy is considered to be 1.0 wt%.
- OSTI ID:
- 22805895
- Journal Information:
- Materials Characterization, Journal Name: Materials Characterization Vol. 145; ISSN 1044-5803; ISSN MACHEX
- Country of Publication:
- United States
- Language:
- English
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