The use of aluminum alloys in automotive and other industries is due to their excellent combination of weight and strength, which is obtained by heat treating. The alloying elements are put in solution by holding the material at a high temperature, and cooling at a rate fast enough to allow them to remain in solution; strengthening is then produced by the precipitation of particles of different size, shape and nature. This work presents the results of the analyses of samples made from cast aluminum alloys hardened by either the precipitation of Mg 2 Si or Al 2 Cu and of an alloy that has both. The samples were solution treated at temperatures adequate for the different alloys and cooled by placing them in water close to boiling. Aging was conducted at two different temperatures (170 and 240°C) in all cases for times as long as 100 hrs. Changes due to aging were documented by microhardeness, microscopical examination and by X-ray diffraction. X-ray examination showed that the peak corresponding to the {311} position shifts the aging condition, indicating changes in the lattice parameter of aluminum, which depends on the type of particle that precipitates.

As automobile manufactures today push the envelope of light weighting technologies, so do they impart opportunities for the development of new thermal processing technologies. In an era of light weighting technology advancement, we see a common trend where steel components are being replaced with lighter weight aluminum components. We see automotive manufactures expanding the use of lightweight technologies and exploiting the use of aluminum materials in high volume general purpose vehicles where in the past these lightweight technologies were relegated to high performance or luxury vehicles. Traditionally we see aluminum being incorporated in various forms and configurations such as castings for powertrains and suspensions and sheet and extruded shapes for the body externals and bumper structures. Today we see lightweight materials being incorporated into high volume automotive platforms in the form of thin walled structural node castings and body structure extrusion stampings.

Aluminum alloys are used intensively by the automotive industry to comply with environmental and fuel consumption regulations. These alloys were first used in the manufacture of power train components, and they have extended their use in parts and assemblies of structural components. Power train and structural components have to be heat treated to achieve the strength and hardness demanded, which imply solution treating, quenching and aging. Quenching is the most critical part of processing, as the material has to be cooled at rates high enough to allow for the hardening elements to remain in solution, but the rate has to be controlled to avoid distortion or, in some cases, catastrophic failure. Distortion is associated with the geometry of the piece, as heavy components have sections of different volume, which will cool at different rates, or, in the case of long thin pieces, warpage may arise from variations in cooling rate along the length of the part. This work presents the results of a series of tests carried out with the aim to evaluate the variation of the heat transfer coefficients that take occur in pieces made of a heat treatable wrought aluminum alloy cooled in different media. The heat transfer coefficients were used to compute the temperature distribution of a modified version of the Navy C specimen.

The solution quenching process is a critical heat treatment process for aluminum alloys to obtain better strength and a homogeneous super solid solution. In this paper, the mechanical properties of Al-5%Cu-0.4%Mn in the as-quenched state are tested. The alloy, designated as ZL205 (Chinese standard), has a chemical composition similar to a 2xxx series aluminum alloy and is used for constructing large thin wall components. The ZL205A alloy shows good performance under loading at room temperature while losing its toughness and exhibiting tensile brittleness, which is unexpected at elevated temperatures (especially at 300 °C). After observing the fracture sections of ZL205A at room temperature and at 300 °C, it may be concluded that one possible reason leading to this phenomenon may be the formation of the T phase at grain boundaries. Such a hypothesis is validated and discussed with the help of SEM observations.

Ti-6Al-4V alloy is characterized to be sensitive to heat treatment and deformation. This paper focuses on microstructural evolution and variation in mechanical properties with respect to the deformation and change in the heat treatment cycle. Different heat treatment cycles such as mill annealing, solution treatment and beta solution treatment followed by annealing were carried out on deformed and undeformed Ti-6Al-4V samples. Heat treated samples were studied using optical and scanning electron microscopy. Also different mechanical tests (i.e. tensile test, fracture toughness test) were conducted and results were analyzed. Large variation in mechanical properties and microstructures were found out with different heat treatment cycles. Fracture toughness was found to be high for beta solution treatment samples than the mill annealed and solution treated samples and the reason for the same has been analyzed.