Microstructures and Properties of V-Modified A380 Aluminum Alloy Produced by High Pressure Rheo-Squeeze Casting with Compound Field Treatment

Chong Lin,Li Zeng,Hanxin Chen,Xiaogang Fang,Shusen Wu

doi:10.3390/met11040587

Abstract

The melt of V-modified A380 alloy aluminum alloy was treated by compound field of ultrasonic vibration (UV) and electromagnetic stirring (ES) around liquidus temperatures. Then the high pressure rheo-squeeze casting (HPRSC) process was used to produce an ingot with the alloy melt obtained. The results indicate that the polygonal Si2V phase is precipitated after adding vanadium to the alloy. With the increasing of V content from 0 to 1.05%, the average length and volume fraction of β-Al5FeSi phase is decreased to 30 μm and 1.44%, respectively. The refinement effects of UV, ES, and UV-ES compound field on the microstructure of the gravity casting alloy are as follows: UV-ES > UV > ES. When the pressure is increased from 0 to 400 MPa, the size of primary α-Al is decreased gradually, the morphology of β-Al5FeSi phase is changed from an acicular to a fine fibrous-like one, and the polygonal Si2V phase is refined to fine particle with an average grain diameter of about 8 μm. The ultimate tensile strength (UTS), yield strength (YS), and elongation of the alloy without V are lower than that of the alloy with 0.7% V under the same pressure. When the pressure is 400 MPa, the UTS, YS, and elongation of T6 heat-treated HPRSC alloy with 0.7% V are 301 MPa, 182 MPa, and 3.3%, respectively. With the decrease in the length of β-Al5FeSi phase, the quality index of the HPRSC alloy is increased.

Highlights

A380 aluminum alloy is the most common die-casting aluminum alloy
Various methods can be used to reduce the detrimental influence of Fe-rich phase including rapid solidification, melt superheat treatment, adding neutralizing elements, and ultrasonic vibration (UV)
The results showed that the addition of V could slightly change the needle-like β-Fe phase to more globular shape

Summary

Introduction

A380 aluminum alloy is the most common die-casting aluminum alloy. It is widely used in the automotive and electrical industries such as motor frames and housings. Various methods can be used to reduce the detrimental influence of Fe-rich phase including rapid solidification, melt superheat treatment, adding neutralizing elements, and ultrasonic vibration (UV). Rajabi et al [1] found that the length of needle-like δ-Fe phase in the gasatomized powder of Al-20Si-5Fe alloy was about 3.6μm. Further increasing the cooling rate by using a melt spinning process will lead to the supersaturation of the Al matrix and the absence of the Fe-rich phase. The rapid solidification process is complicated and the subsequent consolidation stage is imperative to get the final product. Ahmad et al [2]

Methods

Results

Conclusion