Additive Manufacturing (AM)

The need for less weight and high-performance materials in manufacturing industries has continuously led to the development of lightweight materials through the use of advanced additive manufacturing (AM). The race of lightweight and high-performance metals continue to evolve as this continuously provides better understanding about connection existing between material processing, microstructural development, and material properties. AM technique is an interesting manufacturing process that is employed in production of engineering components with improved properties. The choice of titanium and its alloys in structural applications are attributed to their superior strength-to-weight ratio and high corrosion resistance. This chapter looked at different additive manufacturing (AM) techniques developed for the processing of lightweight metals, their strengths, and limitations. The chapter also looked at the role and contribution of AM to the 4th industrial revolution, processing, and application of titanium aluminide for high temperature applications.

Adhesive Joints with Laser Shaped Surface Microstructures

One of the most commonly applied methods of joining dissimilar materials is gluing. This could be mainly attributed to the applicability of this technique in various industries. The article presents a method of material surface treatment, which increases the shear strength of adhesive joints for lightweight metals such as aluminum with plastics. For this purpose, laser surface microstructuring was performed on each of the selected construction materials. As a result of the performed treatment, the active surface of the glued area was increased, which increased the adhesive strength. The picosecond laser with UV radiation used in the research is TruMicro 5325c with which material can be removed as a result of the cold ablation phenomenon. The applied parameters of the laser device did not cause thermal damage to the surface of the microstructured materials, which was confirmed by microscopic examination. Laser micromachining did not deteriorate the degree of wetting of the tested materials, either, as was confirmed by the contact angle and surface energy measurements with the use of water as the measuring liquid. In investigated cases of microstructure types, the presented method significantly increased the shear strength of the joints formed, as demonstrated by the presented strength test results. Research has shown that created joints with microstructure made according to the described method, are characterized by a significant increase in strength, up to 376%, compared to materials without microstructure. The presented results are part of a series of tests aimed at selecting the operating laser parameters for the implementation of geometric shapes of microstructures which will increase the strength of adhesive joints in selected materials.

Advances in Processing and Mechanical Behavior in Lightweight Metals and Alloys

The demand for lightweight metals and related alloys is still the most suitable solution to many high-tech applications, including sports equipment and automotive components where alternate movements require low inertia [...]

An experimental insight of friction stir welding of dissimilar AA 6061/Mg AZ 31 B joints

In the present scenario, aerospace and automobile industries depend on lightweight materials such as magnesium and aluminum alloys because of their great balance between mechanical properties and weight ratio. Despite these benefits during the joining process of these dissimilar materials by welding, many challenges arises. The prominent one is related to the low melting points of these lightweight metals which make it almost impossible the joining using conventional arc welding techniques. To tackle this challenge, Friction Stir Welding (FSW) can be considered as a promising candidate tool. In this study, to demonstrate the FSW performances of joining two dissimilar materials we have investigated the joining of AA 6061 and Mg AZ 31 B using a built-in house a modified milling machine. The dissimilar combinations of AA 6061 and Mg AZ 31 B joints were successfully joined by embedding different welding conditions and varying the offset distance. The mechanical performances were evaluated by conducting specific mechanical tests such as micro-hardness, tensile, and impact tests, respectively. To explain the mechanical results, we have applied optical microscopy observation on the microstructure associated with the bonding location. The results prove that the strength of the Friction Stir Welded joints is much higher as compared to other techniques especially in terms of dissimilar metals.

Emerging Trends in Single Point Incremental Sheet Forming of Lightweight Metals

Lightweight materials, such as titanium alloys, magnesium alloys, and aluminium alloys, are characterised by unusual combinations of high strength, corrosion resistance, and low weight. However, some of the grades of these alloys exhibit poor formability at room temperature, which limits their application in sheet metal-forming processes. Lightweight materials are used extensively in the automobile and aerospace industries, leading to increasing demands for advanced forming technologies. This article presents a brief overview of state-of-the-art methods of incremental sheet forming (ISF) for lightweight materials with a special emphasis on the research published in 2015–2021. First, a review of the incremental forming method is provided. Next, the effect of the process conditions (i.e., forming tool, forming path, forming parameters) on the surface finish of drawpieces, geometric accuracy, and process formability of the sheet metals in conventional ISF and thermally-assisted ISF variants are considered. Special attention is given to a review of the effects of contact conditions between the tool and sheet metal on material deformation. The previous publications related to emerging incremental forming technologies, i.e., laser-assisted ISF, water jet ISF, electrically-assisted ISF and ultrasonic-assisted ISF, are also reviewed. The paper seeks to guide and inspire researchers by identifying the current development trends of the valuable contributions made in the field of SPIF of lightweight metallic materials.

High Strength and High Electrical Conductivity Al Nanocomposites for DC Transmission Cable Applications

Aluminum is one of the most abundant lightweight metals on Earth with broad practical applications, such as in electrical wires. Although traditional aluminum manufacturing by alloying, deformation and thermomechanical means addresses the balance between high strength and high conductivity, adding metallic ceramic nanoparticles into the aluminum matrix can be an exciting alternative approach to mass produce aluminum electrical wires. Here, we show a new class of aluminum nanocomposite electrical conductors (ANECs), with significantly higher hardness (130 HV) and good electrical conductivity (41% IACS). This ANEC is composed of Al and dispersed TiB2 nanoparticles, as confirmed by XRD scanning and SEM imaging. We further observed an unusual ultra-fine grain (UFG) size when slow cooling ANEC samples, as a grain as small as 300 nm was clearly captured in FIB images. We believe that the significant hardness enhancement can be partially attributed to the UFG. Our investigation and theoretical analysis further validated that UFG can be achieved when nanoparticles are uniformly dispersed and distributed in the aluminum matrix, and this understanding is important for the development of Al nanocomposite wires with high strength and high electrical conductivity.

The effect of palm kernel shell ash reinforcement on microstructure and mechanical properties of Al-Mg-Si metal-matrix composites

Aluminium is one of the lightweight materials that have a major contribution in numerous applications globally and it is also considered less expensive compared with other lightweight metals such as titanium and magnesium. As a result of some engineering applications’ requirements of better hardness and strength of material with lesser weight, researchers’ attention is drawn to the enhancement of the mechanical properties of accessible aluminium alloys. This study was conducted to study the microstructure and mechanical properties of a composite Al-Mg-Si matrix with varying weight percentages (0, 4, 6 and 8 wt. %) of palm kernel ash (PKSA) reinforcement, which were denoted correspondingly as C1–C4. The PKSA was obtained at a calcination temperature of 850 °C, XRD and XRF analyses were conducted to characterize it. The formulated samples were then ball-milled using two roll mills for about 60 hours to achieve a near homogeneity of the composites. The SEM image of the reinforced samples (C2 and C3) revealed that there were many networks of coalesced or necked particles while individual particles are hardly found, which is an indication of a high degree of densification ratio percentage of PKSA. The results also showed that there was an increase in hardness (44.4%), modulus of rupture (37.4%) and impact strength (252.03%) of Al-Mg-Si matrix composites (C3) in comparison with the unreinforced matrix material.

Mit explorativer Datenanalyse und Data Mining zu hoch effizienten polymeren Tribo-Schicht-Systemen

Since current developments in machine building and automotive industry are dealing with the amplification of energy efficiency and sustainability of components, the reduction of friction and wear losses plays the most important key role. A further aspect of energy saving by mass reduction can be taken into account by substituting steel by lightweight metals. To fulfill these requirements, this study focuses on the development of a tribo-coating system, based on PEEK (poly-ether-ether-ketone) as a base coating material for Al substrates. The coating is applied by using laser radiation to increase the energy efficiency of the coating process on the one hand and to reduce thermal stress on the component on the other hand. Furthermore, the laser process improves the mechanical prosperties of the polymeric coating. In the first step the correlation between the coating process parameters and the resulting coating morphology accompanied by its mechanical properties and the tribological behavior was elucidated by using explorative data analysis. Here, the influence of different wear and/or friction reducing additives and their variable concentrations was also taken into account, while the tribological response of the resulting coating systems was examined and valuated under dry sliding conditions. Using data mining, the most dominant correlations between the process parameters and the tribological answer of the coating system could be found. Utilizing these findings, the process parameters for different additives in the PEEK dispersions could be optimized, and a multilayer system was established, which combines high corrosion and wear protection accompanied by a tribo-film formation resulting in low friction and an increased lifetime of the coating system.

Effect of Cavitation Peening on Fatigue Properties in Friction Stir Welded Aluminum Alloy AA5754

Friction stir welding (FSW) is an attractive solid-state joining technique for lightweight metals; however, fatigue properties of FSWed metals are lower than those of bulk metals. A novel mechanical surface treatment using cavitation impact, i.e., cavitation peening, can improve fatigue life and strength by introducing compressive residual stress into the FSWed part. To demonstrate the enhancement of fatigue properties of FSWed metal sheet by cavitation peening, aluminum alloy AA5754 sheet jointed by FSW was treated by cavitation peening using cavitating jet in air and water and tested by a plane bending fatigue test. The surface residual stress of the FSWed part was also evaluated by an X-ray diffraction method. It was concluded that the fatigue life and strength of FSWed specimen were improved by cavitation peening. Whereas the fatigue life at σa = 150 MPa of FSWed specimen was about 1/20 of the bulk sheet, cavitation peening was able to extend the fatigue life of the non-peened FSW specimen by 3.6 times by introducing compressive residual stress into the FSWed part. This is the first paper to demonstrate the improvement of fatigue properties of FSWed metallic sheet by cavitation peening.