Effects of Cr and Er microalloying on the microstructural evolution and mechanical properties of high-pressure die-cast Al-Si-Ni alloys

Peng Hu; Xiaolu Hong; Liying Cui; Jiang Zhang; Yinjiang Peng; Dahui Chen; Peng Hu; Xiaolu Hong; Liying Cui; Jiang Zhang; Yinjiang Peng; Dahui Chen

doi:10.3934/matersci.2026017

AIMS Materials Science

2026, Volume 13, Issue 2: 300-314. doi: 10.3934/matersci.2026017

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Effects of Cr and Er microalloying on the microstructural evolution and mechanical properties of high-pressure die-cast Al-Si-Ni alloys

Ningbo Branch of Chinese Academy of Ordnance Science, Ningbo, 315103 China

Received: 03 February 2026 Revised: 07 March 2026 Accepted: 16 March 2026 Published: 06 April 2026

The effects of Cr and Er microalloying on the microstructural evolution and mechanical properties of high-pressure die-cast hypereutectic Al-Si-Ni alloys were systematically investigated. The morphology and distribution of primary Si were quantitatively analyzed using optical microscopy and ImageJ software, and the tensile properties were evaluated at room temperature and 350 ℃. The results indicate that Cr addition promotes the formation of CrSi₂ phases, which act as heterogeneous nucleation sites, increasing the nucleation rate and suppressing the growth of primary Si. Er addition refines primary Si through interfacial segregation and the modification of growth kinetics; however, excessive Er leads to the precipitation of Al₃Er and weakens the refinement effect. As a result of the refined and more homogeneous distribution of primary Si, both Cr- and Er-containing alloys exhibited enhanced tensile strength and ductility at room temperature and 350 ℃. The 0.4Cr alloy showed the best mechanical performance among the investigated compositions, and the optimal Er addition was identified to be approximately 0.2 wt.%. This work provides guidance for the microalloying design of hypereutectic Al-Si-Ni alloys with improved high-temperature mechanical performance.
- hypereutectic Al-Si-Ni alloy,
- microalloying,
- primary Si,
- mechanical properties
Citation: Peng Hu, Xiaolu Hong, Liying Cui, Jiang Zhang, Yinjiang Peng, Dahui Chen. Effects of Cr and Er microalloying on the microstructural evolution and mechanical properties of high-pressure die-cast Al-Si-Ni alloys[J]. AIMS Materials Science, 2026, 13(2): 300-314. doi: 10.3934/matersci.2026017

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Abstract

The effects of Cr and Er microalloying on the microstructural evolution and mechanical properties of high-pressure die-cast hypereutectic Al-Si-Ni alloys were systematically investigated. The morphology and distribution of primary Si were quantitatively analyzed using optical microscopy and ImageJ software, and the tensile properties were evaluated at room temperature and 350 ℃. The results indicate that Cr addition promotes the formation of CrSi₂ phases, which act as heterogeneous nucleation sites, increasing the nucleation rate and suppressing the growth of primary Si. Er addition refines primary Si through interfacial segregation and the modification of growth kinetics; however, excessive Er leads to the precipitation of Al₃Er and weakens the refinement effect. As a result of the refined and more homogeneous distribution of primary Si, both Cr- and Er-containing alloys exhibited enhanced tensile strength and ductility at room temperature and 350 ℃. The 0.4Cr alloy showed the best mechanical performance among the investigated compositions, and the optimal Er addition was identified to be approximately 0.2 wt.%. This work provides guidance for the microalloying design of hypereutectic Al-Si-Ni alloys with improved high-temperature mechanical performance.

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