Process for the production of an aluminum piston for an internal combustion engine

By treating the molten aluminum alloy with phosphorus, strontium, and rare earth modifiers during the production of aluminum pistons for internal combustion engines, and combining this with processes such as mechanical vibration and graded pressure holding casting, a fine-grained and dense nano-precipitated structure is formed. This solves the stress concentration problem caused by coarse silicon phases and improves the tensile strength and fatigue resistance of the piston.

CN122352832APending Publication Date: 2026-07-10ANHUI HIGH TECH POWER TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-04-30
Publication Date
2026-07-10

AI Technical Summary

Technical Problem

In existing aluminum pistons for internal combustion engines, the coarse and sharp silicon phases become stress concentration sources during service, leading to reduced fatigue life and reliability.

Method used

Aluminum alloy melt is treated with a composite modifier of phosphorus, strontium and rare earth (yttrium and lanthanum), combined with mechanical vibration and graded pressure holding casting, followed by solution treatment, graded aging treatment, low-temperature hard anodizing and composite sealing treatment to form a fine-grained and dense nano-precipitated structure.

Benefits of technology

It significantly improves the tensile strength and fatigue resistance of the piston, meeting the long service life requirements of internal combustion engines under high temperature and high pressure cyclic conditions.

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Abstract

This invention relates to a manufacturing process for aluminum pistons for internal combustion engines, comprising the following steps: S1: Phosphorus modifier, strontium modifier, and rare earth modifier are sequentially added to molten aluminum alloy, wherein the amount of phosphorus added is 0.02-0.06 wt%, the amount of strontium added is 0.03-0.08 wt%, and the amount of rare earth modifier is... 0.05-0.15 wt%, with a modification treatment temperature of 740℃-770℃; This invention uses P and Al to form AlP cores, which serve as heterogeneous nucleation sites for primary silicon; rare earth elements Y and La preferentially adsorb onto the surface of the AlP nucleation core, reducing the lattice mismatch between AlP and primary silicon, significantly improving heterogeneous nucleation efficiency and enhancing the high-temperature thermal stability of the core, resulting in significantly refined primary silicon. At the same time, La preferentially occupies the twisting sites of the eutectic silicon growth steps, and Sr subsequently spreads and adsorbs on the pre-modified interface, forming a relay-type interface modification, transforming the eutectic silicon from needle-like to spherical. Y and La form Al3Y and Al3La composite pinning phases at the grain boundaries, effectively inhibiting high-temperature grain growth.
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