A Study on Hot Tearing in Direct Chill Casting of Al-Mn-Mg Alloys Using a Multi-scale Approach

Abstract

A multi-scale approach for simulating hot tearing during the DC casting of aluminum alloys is presented. The novelty of this approach lies in the combination of a macro-scale finite element simulation of the DC casting process with direct prediction of hot tears via a meso-scale multiphysics granular model. This approach is capable of simulating hot tearing initiation, growth, and propagation within a representative volume element of the mushy zone. The change of cooling conditions experienced by the DC cast billet as a result of variations in casting speed as well as non-uniformity of heat extraction from different locations of the billet affect the deformation state, cooling rate, and thermal gradient, which further influence the strain rate, grain size, permeability, and feeding coefficient. Considering all the mentioned parameters, the multi-scale approach emphasizes the fact that hot tearing is a phenomenon resulting from the combination of the tensile deformation and restricted feeding of the mushy zone. The developed hot tearing formation maps identify the locations where hot tearing will occur as predicted by the multi-scale approach for two alloys -AA5182 and AA3104 -thus demonstrating the approach's sensitivity to both processing parameters and alloy composition.

The Role of Solidified Phases on the Hot Cracking of a Large-Size GH4742 Superalloy Ingot

“…Numerous metals, such as aluminium alloys [8,9], magnesium alloys [10,11] and stainless steels [12], are susceptible to hot cracking. Some researchers have found that hot cracking is a complicated phenomenon that can be influenced by mechanical and non-mechanical factors [13][14][15][16][17][18]. Li et al investigated the effects of pouring temperature and mould temperature on the hot cracking tendency of Al-Cu alloys.…”

Design and application of a multichannel “cross” hot tearing tendency device: A study on hot tearing tendency of Al alloys

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Against the background of the lightweight industry, the development of new aluminum alloys with high specific strength and low production cost is one of the main goals in modern industry. However, hot tearing is one of the most serious and irreparable defects in the production of thin-wall, complex and large castings of aluminum alloy, which limits the application of aluminum alloys [1][2][3] . Hot tearing is mainly attributed to insufficient feeding during solidification and the large-size thermal stress and strain at the end of solidification [4] .

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