Effect of ultrasonic and different modification treatments on the microstructure of cast Al-Si-Cu-Mg-Ni alloy

ABSTRACT

The Al-Si-Cu-Mg-Ni alloy is a commonly used piston alloy. In this work, different amounts of phosphorus modifier and Al-2P (Al-2%P) master alloy modifier were added to the original alloy. The ultrasonic melt treatment method was also applied to improved the microstructure of near-eutectic multi-cast Al–Si alloys. Investigation was performed by means of optical microscopy and scanning electron microscopy. The results show that the effect of Al-2P master alloy modifier is more stable. However, the phosphorus modifier requires a higher amount of addition to achieve a refinement effect similar to that of the Al-2P modifier. The external ultrasonic field mainly acts on the AlP particle. The heterogeneous nucleation of the primary Si phase and the AlP clusters formed by the phosphorus modifier are more aggregated than the fine-dispersed AlP particles formed by the Al-2P master alloy modifier in the melt. Hence the ultrasonic melt treatment is more effective for the phosphorus modification.

KEYWORDS:

• Al–Si alloy
• melt ultrasound
• modifier
• microstructure

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the project of China [grant number 41422010605], the major industrial chain project of Shannxi Province [grant number 2018ZDCXL-GY-09-08], and the major R&D project of Shandong Province [grant number 2018JMRH0212]; Overall planning project of Shaanxi Province: [grant number S2018-YF-ZDLGY-0070].