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Characterization of Sm-rich phase and properties of hypereutectic Al-Ni alloys modified by Sm.

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Bibliographic Details
Title:	Characterization of Sm-rich phase and properties of hypereutectic Al-Ni alloys modified by Sm.
Authors:	Mo, Liling¹ (AUTHOR), Duan, Shougang¹ (AUTHOR), Lin, Mingxian¹ (AUTHOR), Chen, Linbo¹ (AUTHOR), Du, Jun¹ (AUTHOR) tandujun@sina.com
Source:	Journal of Alloys & Compounds. Nov2024, Vol. 1005, pN.PAG-N.PAG. 1p.
Subjects:	Tensile strength, Thermal conductivity, Thermal expansion, Thermal properties, Alloys, Hypereutectic alloys
Abstract:	The impact of Samarium (Sm) addition on hypereutectic Al-Ni alloys was systematically investigated, focusing on microstructural changes and thermal-physical, mechanical properties. The addition of 0.1–0.5 wt% Sm resulted in the refinement of primary Al 3 Ni phases from coarse lath-like structures to small particles, enhancing mechanical properties and reducing thermal expansion coefficients (CTE). Thermal conductivity (TC) improved with 0.1–0.3 wt% Sm addition, but declined at the amount of 0.5 wt%. Excessive Sm addition leads to the formation of a Sm-rich phase, characterized by a two-phase mixed structure of Al 11 (Ni, Sm) 3 surrounded by Al 4 Sm. Sm addition lowered the precipitation temperature of the primary Al 3 Ni phase, inducing significant constitutional undercooling and exhibiting a phase refinement effect. The Al-9Ni-0.3Sm alloy showed excellent performance, with a TC of 211.8 W/(m·K), CTE of 17.3×10−6/K (@25–100 °C), ultimate tensile strength of 169.5 MPa, and elongation of 10.4 %. Optimal addition of Sm improved TC, mechanical properties as well as reduced the CTE in the Al alloy at the same time and showed a good modification effect. [Display omitted] • Sm addition refines the primary and eutectic Al 3 Ni phases in the Al-10Ni alloy. • Adding Sm lowers the initial solidification temperature, inducing constitutional undercooling for phase refinement. • Sm modification enhances both thermal-physical properties and mechanical properties. • A new Sm-rich structure forms at higher Sm content, affecting modification and refinement effects in the Al-10Ni alloy. • The Sm-rich structure is determined as a structure of the inner Al 11 (Sm, Ni) 3 phase wrapped by the outer Al 4 Sm phase. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	The impact of Samarium (Sm) addition on hypereutectic Al-Ni alloys was systematically investigated, focusing on microstructural changes and thermal-physical, mechanical properties. The addition of 0.1–0.5 wt% Sm resulted in the refinement of primary Al 3 Ni phases from coarse lath-like structures to small particles, enhancing mechanical properties and reducing thermal expansion coefficients (CTE). Thermal conductivity (TC) improved with 0.1–0.3 wt% Sm addition, but declined at the amount of 0.5 wt%. Excessive Sm addition leads to the formation of a Sm-rich phase, characterized by a two-phase mixed structure of Al 11 (Ni, Sm) 3 surrounded by Al 4 Sm. Sm addition lowered the precipitation temperature of the primary Al 3 Ni phase, inducing significant constitutional undercooling and exhibiting a phase refinement effect. The Al-9Ni-0.3Sm alloy showed excellent performance, with a TC of 211.8 W/(m·K), CTE of 17.3×10−6/K (@25–100 °C), ultimate tensile strength of 169.5 MPa, and elongation of 10.4 %. Optimal addition of Sm improved TC, mechanical properties as well as reduced the CTE in the Al alloy at the same time and showed a good modification effect. [Display omitted] • Sm addition refines the primary and eutectic Al 3 Ni phases in the Al-10Ni alloy. • Adding Sm lowers the initial solidification temperature, inducing constitutional undercooling for phase refinement. • Sm modification enhances both thermal-physical properties and mechanical properties. • A new Sm-rich structure forms at higher Sm content, affecting modification and refinement effects in the Al-10Ni alloy. • The Sm-rich structure is determined as a structure of the inner Al 11 (Sm, Ni) 3 phase wrapped by the outer Al 4 Sm phase. [ABSTRACT FROM AUTHOR]
ISSN:	09258388
DOI:	10.1016/j.jallcom.2024.175990