The heat treatment of the heat-treatable aluminium alloy forgings includes cooling from the solutionising temperature. After heat treatment, residual stresses remain in the forging, which are due to temperature gradients during cooling. The effect of these residual stresses on the forging properties can be significantly influenced by other technological operations, including artificial aging, machining, and surface treatments. The influence of the surrounding environment can also play an important role. Because in connection with the residual stresses after heat treatment we often encounter cracks in forgings, this paper is devoted to an overview of factors that influence cracks. The typical examples of damaged forgings are discussed and explained the circumstances that caused cracks under the influence of residual stresses.

The manufacture of die forgings from Al-Mg-Si type alloys is one of important topics of material and forming technology development. One of innovation factors affecting the forging technology is based on the use of continually cast rods instead of extruded ones. This change of technology is, however, connected with some problems concerning the structure, an inhomogeneous surface layer, surface morphology of cast rods and increased flow stress of the cast structure as well. The present paper deals with some aspects relating to the inhomogeneity of structure, intermetallic phases and thermomechanical treatment. The investigation of the cast and extruded structure was carried out with the help of optical and electron microscopy.

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Stress corrosion cracking (SCC) is a common cause of structural failure. The simultaneous action of the corrosive environment and tensile stresses creates cracks that have an intercrystalline or transcrystalline character. These are cracks with a fragile morphology of the fracture surface without signs of plastic deformation in their vicinity. SCC cracks occur in several alloys. This paper focuses on copper alloys in which this type of failure occurs frequently. Examples from practice show cases where the occurrence of SCC violation was related to the conditions of use of components and their production technologies. The paper does not aim to capture all the influences associated with the occurrence of SCC failure of copper alloy products. SCC stress corrosion crackingCopper alloys Cold deformation Heat treatment Tensile stress

High temperature homogenization annealing of DC cast billets from aluminium alloys used for extrusion pressing is considered as one of substantial technological operations during extrusion processing. The structure of DC cast billets consists of dendrite cell structure and contains coarse and inhomogeneously distributed intermetallic phases of β-AlFeSi and α-Al(Fe,Mn)Si type.Structure after a homogenization annealing is quite decisive for both the final properties of extrusions and the extrudability of the cast structure. The present paper deals with the medium strength heat-treatable EN AW-6082 alloy. It is investigated the effect of heating rate, time at the annealing temperature and the cooling rate of continually cast billets during the homogenization annealing on the changes of electrical conductivity, structure and intermetallic phases.