Hot Tearing of Machinability Improved 2xxx Aluminum Alloy of High Tin Content with Manganese and Chromium Addition

A201 alloy is the strongest cast aluminum alloy, but it is considered one of the most difficult aluminum alloys to cast due to its susceptibility to hot tearing during solidification. Semi-solid casting, which characterizes fine near-globular or non-dendritic grains and relatively narrow solidification range, is potential to reduce hot cracking tendency of alloys. In this present work, semi-solid slurries of A201 alloy were prepared using Swirled Enthalpy Equilibrium Device (SEED) technique and then injected into a self-designed high pressure hot tearing mold. The microstructures of A201 semi-solid slurries with different pouring temperatures were examined. Effects of different casting pressures on the hot tearing sensitivity of A201 have been investigated. This study finds that SEED is capable of producing satisfying A201 semi-solid slurries. Lower pouring temperatures produce A201 semi-solid slurries with finer and rounder grains as well as more uniform microstructure distribution. Increasing the intensification pressure significantly decreases the hot treating tendency of A201 alloy. When the pressure reaches to 90 MPa and the mold temperature of about 250 °C, the hot tearing susceptibility (HTS) index value is nearly zero, which means almost no surface cracks are found in the semi-solid A201 die casting parts.

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Nonmechanical criteria proposed for prediction of hot tearing sensitivity in 2024 aluminum alloy

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(18)64718-1 ◽

2018 ◽

Vol 28 (5) ◽

pp. 848-857 ◽

Cited By ~ 3

Author(s):

M.H. GHONCHEH ◽

S.G. SHABESTARI ◽

A. ASGARI ◽

M. KARIMZADEH

Keyword(s):

Aluminum Alloy ◽

Hot Tearing ◽

2024 Aluminum Alloy

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Effect of Sc on the Hot Cracking Properties of 7xxx Aluminum Alloy and the Microstructure of Squeeze Castings

Materials ◽

10.3390/ma14226881 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6881

Author(s):

Yongtao Xu ◽

Zhifeng Zhang ◽

Zhihua Gao ◽

Yuelong Bai ◽

Purui Zhao ◽

...

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Aluminum Alloy ◽

Performance Test ◽

Casting Process ◽

Hot Cracking ◽

Hot Tearing ◽

Average Grain Size ◽

Cylindrical Parts ◽

Series Aluminum Alloy

In this paper, the effect of adding the refiner Sc to the high Zn/Mg ratio 7xxx series aluminum alloy melt on the hot tearing performance, microstructure, and mechanical properties of the alloy is studied. The hot tearing performance test (CRC) method is used to evaluate the hot tearing performance of the alloy. The squeeze casting process was used to form solid cylindrical parts to analyze the structure and properties of the alloy. This study shows that the hot cracking sensitivity of the alloy after the addition of the refiner Sc is significantly reduced. The ingot grain size is significantly reduced, and the average grain size is reduced from about 86 μm to about 53 μm. While the mechanical properties are significantly improved, and the tensile strength reduced from 552 MPa is increased to 571 MPa, and the elongation rate is increased from 11% to 14%.

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