Search Results (8)

This paper presents an investigation on the forming characteristics of the tailor rolled blank of an aluminum alloy (Al-TRB) during three-point bending at room temperature through experiments and finite element simulations. The strain distribution, spring-back characteristics, and metal flow law of 6000 series Al-TRB during three-point bending are explored. The prepared Al-TRB has good bending properties, and no surface cracks appear in the bending region of the Al-TRB when bent to 180°. Surface roughening occurs on the outside of the bending region. Since the strain in the thick zone is greater than that in the thin zone, the surface roughening in the thick zone is more obvious than that in the thin zone. The spring-back angle in the thin zone is higher than that in the thick zone after three-point bending, and the overall spring-back angle of Al-TRB becomes larger with an increasing bending angle. When the transition zone of Al-TRB is centered and the length of the transition zone is certain, as the length of the equal-thickness zone increases, the spring-back angle of the thin zone is larger, while the spring-back angle of the thick zone is smaller. Under the premise of a certain total length of Al-TRB and the length of the transition zone, the larger the length proportion of the thin zone, the larger the overall spring-back angle of Al-TRB, and the larger the length proportion of the thick zone, the smaller the overall spring-back angle of Al-TRB. In addition, a slight metal flow phenomenon exists during three-point bending, which shows that the metal in the bending region will flow to the thick zone, and the metal at the edge will flow to the thin zone. At the same time, there are localized thickening and thinning phenomena in Al-TRB. This study is helpful because it provides theoretical guidance for designing molds for the actual production of Al-TRB parts for automotives. Full article

Sustainability is one of the biggest values of today and for the future of our society; a responsible usage of material in every sector is fundamental to achieving sustainability goals. Aluminum alloys are some of the most promising materials in terms of strength and weight, but their production implies the emission of a high amount of CO₂. For that reason, the study and development of aluminum alloys with increasing scrap content play a central role in future applications. In the current study, two sheet-aluminum 6181 alloys with different scrap content were analyzed and compared with a 6181 alloy coming from primary production. The alloys were compared in terms of chemical composition, microstructure, tensile properties, and forming behaviors. The results showed that the alloys coming from secondary productions contained a higher amount of manganese, iron, and copper. The metallurgical and mechanical behaviors were very similar to those of the primary produced alloy. Nevertheless, a drop in formability was shown in the aluminum alloys containing a high scrap amount when stressed in a biaxial condition. The study demonstrated the viability of 6181 alloy production using a high scrap amount, highlighting the main difference with the same alloy coming from primary route production. Full article

The aluminum alloys corresponding to the 6000 series are mainly manufactured by mechanical forming processes. Their properties are enhanced by the homogeneous distribution of intermetallic phases such as β-Al₅FeSi or α-Al_x (Fe, Mn) Si. By thermal homogenization treatment, the intermetallic compound β-Al₅FeSi changes its morphology from a needle type with a monoclinic structure to an acicular form known as α-Al₁₂(Fe, Mn)₃Si with an fcc structure. In the present study, samples of the 6063 alloy were subjected to different temperatures of homogenization (798, 823, and 848 K) and treatment times from 0 to 660 min (in intervals of 30 min) to evaluate their effects on the microstructures and morphologies of the intermetallic phases. For the kinetic study, the microstructures of the β and α intermetallic phases were quantified using the Image-Pro software. The results indicate that as the temperature and homogenization time increase, the percentage of phase α also increments. The results of the kinetic analysis revealed that the β → α transformation is controlled by two stages; the first corresponds to the diffusion of Mn atoms from the matrix to the interface of reaction for the formation of the intermetallic phases, while the second corresponds to the nucleation and growth of the iron- and manganese-rich intermetallic phases. Full article

The range of available aluminum alloy powders for laser powder bed fusion (LPBF) is restricted to mainly Al–Si based alloys. Currently aluminum alloy powders, designed for lightweight application, based on Al–Mg (5000 series), Al–Si–Mg (6000 series), or Al–Zn–Mg (7000 series), cannot be processed by LPBF without solidification cracks. This has an impact on the potential of LPBF for lightweight applications. In fusion welding, solidification cracks are eliminated by using filler materials. This study aims to transfer the known procedure to LPBF, by supplementing EN AW-5083 (AlMg4.5Mn0.7) with AlSi10Mg. EN AW-5083 and two modifications (+7 wt.% and +15 wt.% AlSi10Mg) were produced by LPBF and analyzed. It was found that, in EN AW-5083, the solidification cracks have a length ≥200 µm parallel to the building direction. Furthermore, the solidification cracks can already be eliminated by supplementing 7 wt.% AlSi10Mg. The microstructure analysis revealed that, by supplementing AlSi10Mg, the melt pool boundaries become visible, and the grain refines by 40% relative to the base alloy. Therefore, adding a low melting point phase and grain refinement are the mechanisms that eliminate solidification cracking. This study illustrates a practical approach to eliminate solidification cracks in LPBF. Full article

To evaluate the prediction accuracy of the anisotropic yield function, we propose an original cruciform hole expansion test. Displacements on two axes were applied to the cruciform specimens with a hole in the center. The thickness strain in the region near the hole was compared to the simulation results. Because this forming test is free of friction and bending, it is an appropriate method to assess the anisotropic yield function without the influences of friction or the Bauschinger effect, or the need to consider the stress-strain curve in high-strain region. Hill1948, YLD2000-2D, and spline yield function which is an improved version of the Vegter model were selected, and 6000 series aluminum alloy sheets (A6116-T4) were used in this study. The parameter identification method of the spline yield function also proposed in this paper using the pseudo plane strain tensile test and optimization software. As a result, the spline yield function has better predictive accuracy than the conventional anisotropic yield functions Hill1948 and YLD2000-2D. Full article

Many lightweight materials, including aluminum alloy, magnesium alloy, and plastic, have been used for automotives. Aluminum alloy—the most commonly utilized lightweight metal—has poor resistance spot weldability owing to its inherent properties, which demand the development of welding solutions. Various welding techniques are utilized to improve the resistance spot weldability of aluminum alloy, including DeltaSpot welding. However, the technological development for welding dissimilar metals (aluminum alloy and steel) required for vehicle body assembly is still in its nascent stages. This study proposes DeltaSpot welding (a resistance spot welding process with spooling process tapes) using the alloy combination of 6000 series aluminum alloy (Al 6K32) and 440 MPa grade steel (SGARC 440). The welding characteristics of the main process parameters in DeltaSpot welding were analyzed and the weldability of the combination of the aluminum alloy, Al 6K32, and 440 MPa grade steel was evaluated. In addition, the characteristics of the intermetallic compound layer between the 440 MPa grade steel and Al 6K32 sheets were identified via scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS). Full article

In the current work, the evolutions of grain and dislocation microstructures are investigated on the basis of plane strain tension and simple shear tests for an interstitial free steel (DC06) and a 6000 series aluminum alloy (AA6016-T4). Both materials are commonly-used materials in the automobile industry. The focus of this contribution is on the characterization and comparison of the microstructure formation in DC06 and AA6016-T4. Our observations shed light on the active mechanisms at the micro scale governing the macroscopic response. This knowledge is of great importance to understand the physical deformation mechanisms, allowing the control and design of new, tailor-made materials with the desired material behavior. Full article

Present research work evaluates the influence of both density and size on the treatability of Aluminum-based (6000 series) foam-parts subjected to a typical solid solution heat treatment (water quenching). The results are compared with those obtained for the bulk alloy, evaluating the fulfilment of cooling requirements. Density of the foams was modeled by tomography analysis and the thermal properties calculated, based on validated density-scaled models. With this basis, cooling velocity maps during water quenching were predicted by finite element modeling (FEM) in which boundary conditions were obtained by solving the inverse heat conduction problem. Simulations under such conditions have been validated experimentally. Obtained results address incomplete matrix hardening for foam-parts bigger than 70 mm in diameter with a density below 650 kg/m³. An excellent agreement has been found in between the predicted cooling maps and final measured microhardness profiles. Full article