Possible Effects and Mechanisms of Ultrasonic Cavitation on Oxide Inclusions during Direct-Chill Casting of an Al Alloy

Yun Zhang,Ripeng Jiang,Fang Dong,Xiaoqian Li,Ruiqing Li,Yilong Yang,Pinghu Chen

doi:10.3390/met8100814

Yun Zhang, Ripeng Jiang + Show 5 more

Open Access

https://doi.org/10.3390/met8100814

Copy DOI

Journal: Metals	Publication Date: Oct 11, 2018
Citations: 17	License type: CC BY 4.0

Affiliation: Central South University, Peking University

Abstract

Oxide films or inclusions can reduce the continuity and integrity of materials and they always lead to a significant reduction in the mechanical properties of an aluminum alloy. They can greatly reduce the plastic flow behavior of materials, thus affecting the subsequent processing performance. Therefore, an effective ultrasonic assisted preparation technology has been applied to industrial manufacturing of large-scale aluminum alloy ingots (with diameter: Φ = 1250 mm and height: h = 3750 mm). However, the mechanisms of ultrasonic purification on the large-scale ingots are not clear. Therefore, a number of aluminum alloy casting experiments were carried out to produce a conventional hot top semi-continuous ingot (CHTI) and an ultrasonic hot top semi-continuous ingot (UHTI) in this work. The microstructures of CHTI and UHTI were analyzed by optical microscopy (OM) and scanning electron microscopy (SEM). The results indicated that there were some oxide film defects in the CHTI but some finely dispersed inclusion particles were discovered in the UHTI. The X-ray diffraction (XRD) data showed that the component of inclusion was Al2O3. According to the different cavitation effects of the different areas of the molten aluminum, the process of ultrasonic purification was divided into three periods and the mechanisms in each period were separately studied.

Highlights

IntroductionThe 2219 Al alloy has been used for manufacturing various aerospace components (i.e., oxidizer and fuel tanks) attributable to its high strength, high fracture toughness, and reliable weldability [1,2]
The 2219 Al alloy has been used for manufacturing various aerospace components attributable to its high strength, high fracture toughness, and reliable weldability [1,2].The quality and performance of the large-sized ingots are very important in the realization of performance and the technical target in large-scale aerospace components [3]
We found small irregular particles near the cavity in the fracture exceeded the interface bonding strength between the second phase particles or inclusions and the

Summary

Introduction

The 2219 Al alloy has been used for manufacturing various aerospace components (i.e., oxidizer and fuel tanks) attributable to its high strength, high fracture toughness, and reliable weldability [1,2]. The quality and performance of the large-sized ingots are very important in the realization of performance (high strength, lightweight, stress-corrosion resistance, and stability) and the technical target in large-scale aerospace components [3]. It is urgently necessary to produce high-performance large-sized aluminum ingots to manufacture high-performance components that can adapt to complex working conditions. Many scholars like Eskin [9,10], Li [11], and Abramov [12,13] have studied the mechanisms of ultrasonic treatment on a liquid alloy.

Methods

Results

Discussion

Conclusion