The purpose of this article is to better understand the behavior of the residual stresses in aluminium alloy plates by using mathematical modelling. Quenching of aluminium alloy plates causes an uneven temperature variation in aluminum alloy plates, and elastic and elasto-plastic deformations occur inside the material. The latter causing the formation of deformations and residual stresses. The non-linear thermo-mechanical direct coupled analysis of the quenching process for a 6061 aluminium alloy plate was achieved by using ANSYS finite element software. The residual stresses due to solid thermal effects were determined by calculation of the Third principal stresses, the most negative or compressive. The developed mathematical model offers a support in the understanding the behavior of the residual stresses in aluminium alloy plates and a better control of them.

In recent decades, due to the increase in computing power, mathematical modelling has experienced a fulminant development in almost all areas. The aluminium industry is one of these areas. One of the main processes for improving the properties of certain aluminium alloys is the solution heat treatment and quenching process. The most common quenchant used for aluminium alloys is water. The main advantage of using a water quenchant is that water can provide the rapid quenching. By considering the temperature dependence of the thermo-physical properties, the non-linear thermo-mechanical direct coupled analysis of the quenching process for a 6061 aluminium alloy plate was achieved. The structural stress due to solid thermal effects were studied by using ANSYS finite element software. The quenching rate, which determines the plate deformation after quenching, was estimated and validated on independent equipment for the research of aluminium alloy quenching process. The developed mathematical model serves as a tool by simulation of various scenarios that may occur in the industrial process.

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The quenching is one of the most used mechanisms for increase the strength of aluminium alloys sheets. The purpose of quenching is to keep the super-saturated solid solution formed during the solution heat treatment as intact by rapid cooling. In order to establish the influence of the addition of polymer in the quenching water on the distortion and residual stresses of the aluminium alloy sheets, several tests were performed with different concentrations of the polymer in demineralized water. The experiments were performed on 6082 aluminium alloy sheets with a thickness of 5 mm. The quenching of the samples was done by immersion in a stainless steel vessel with a capacity of 10 liters. The obtained results show that the addition of polymer in demineralized water positively influences the deformation of aluminium alloy sheets. In this way, a correlation between the polymer concentration and the deformation of the plates was established. Regarding the internal stresses, no correlation was identified with the level of polymer used in demineralized water.

We investigated roll-cladded aluminum structures consisting of a layer of Al4045 on Al3003 with a non-destructive laser-ultrasound technique. We determined the thickness of the cladding layer based on the dispersion of the fundamental guided wave propagating along the surface. We analyzed eight surfaces, with cladding thicknesses ranging from 0 to approximately 400μm The inversion of the dispersion data to obtain the thickness yielded in consistent results, which we compare to reference values obtained from micrographs. For the optimization procedure we allowed the material properties to be free parameters, but constrained them to be equal for all samples.