Improvement of Solidification Structure Uniformity in Al-Cu Alloy Casting Process

Xueting Li

DOI: https://doi.org/10.64486/m.65.3.10
Online publication date: January 19, 2026

Abstract: Aluminum–copper alloys are core lightweight materials in aerospace applica-tions; however, their casting is prone to grain size imbalance and Al₂Cu phase segregation. To address these issues, this study focused on an Al–6.07 wt.% Cu al-loy and employed a three-factor, three-level orthogonal experimental design using squeeze casting. The effects of pouring temperature, forming pressure, and holding time on solidification uniformity were investigated using metallographic micros-copy, SEM, and EPMA. The results indicated that the optimal process parameters were a pouring temperature of 730 °C, a forming pressure of 170 MPa, and a hold-ing time of 13 s, combined with aging at 120 °C for 4 h. Under these conditions, the grain size standard deviation (GSSD) of the surface and core was reduced to 7.3 μm and 13.5 μm, respectively, while the Al₂Cu phase segregation degree decreased to 0.14. Consequently, the tensile strength reached 342 MPa, with a microhardness of 120 HV. The study confirms that the proposed “pressure–temperature–solute” coupling mechanism effectively suppresses segregation, providing both theoretical insight and process guidance for the mass production of high-load-bearing alloy components.

Keywords: Al–Cu alloy; squeeze casting; solidification structure uniformity; process parame-ters; Al₂Cu phase

This article is published online first and will appear in Metalurgija, Vol. 65, Issue 3 (2026).