Materials undergo various loading conditions during different manufacturing processes, including varying strain rates and temperatures. Research has shown that the deformation of metals and alloys during manufacturing processes such as metal forming, machining, and friction stir welding (FSW), can reach a strain rate ranging from 10−1 to 106 s−1. Hence, studying the flow behavior of materials at different strain rates is important to understanding the material response during manufacturing processes. Experimental data for a low strain rate of <101 s−1 and a high strain rate of >103 s−1 are readily available by using traditional testing devices such as a servo-hydraulic testing machine and the split Hopkinson pressure bar method, respectively. However, for the intermediate strain rate (101 to 103 s−1), very few testing devices are available. Testing the intermediate strain rate requires a demanding test regime, in which researchers have expanded the use of special instruments. This review paper describes the development and evolution of the existing intermediate strain rate testing devices. They are divided based on the loading mechanism; it includes the high-speed servo-hydraulic testing machines, hybrid testing apparatus, the drop tower, and the flywheel machine. A general description of the testing device is systematically reviewed; which includes the working principles, some critical theories, technological innovation in load measurement techniques, components of the device, basic technical assumption, and measuring techniques. In addition, some research direction on future implementation and development of an intermediate strain rate apparatus is also discussed in detail.

Nickel-based alloys have had extensive immersion in the manufacturing world in recent decades, especially in high added value sectors such as the aeronautical sector. Inconel 718 is the most widespread in terms of implantation. Therefore, the interest in adapting the manufacture of this material to additive manufacturing technologies is a significant objective within the scientific community. Among these technologies for the manufacture of parts by material deposition, plasma arc welding (PAW) has advantages derived from its simplicity for automation and integration on the work floor with high deposition ratios. These characteristics make it very economically appetizing. However, given the tendency of this material to form precipitates in its microstructure, its manufacturing by additive methods is very challenging. In this article, three deposition conditions are analyzed in which the energy and deposition ratio used are varied, and two cooling strategies are studied. The interpass cooling strategy (ICS) in which a fixed time is expected between passes and controlled overlay strategy (COS) in which the temperature at which the next welding pass starts is controlled. This COS strategy turns out to be advantageous from the point of view of the manufacturing time, but the deposition conditions must be correctly defined to avoid the formation of Laves phases and hot cracking in the final workpiece.

Gas Metal Arc Welding (GMAW) is a manufacturing technology included within the different Wire Arc Additive Manufacturing alternatives. These technologies have been generating great attention among scientists in recent decades. Its main qualities that make it highly productive with a large use of material with relatively inexpensive machine solutions make it a very advantageous technology. This paper covers the application of this technology for the manufacture of thin-walled parts. A finite element model is presented for estimating the deformations in this type of parts. This paper presents a simulation model that predicts temperatures with less than 5% error and deformations of the final part that, although quantitatively has errors of 20%, qualitatively allows to know the deformation modes of the part. Knowing the part areas subject to greater deformation may allow the future adaptation of deposition strategies or redesigns for their adaptation. These models are very useful both at a scientific and industrial level since when we find ourselves with a technology oriented to Near Net Shape (NNS) manufacturing where deformations are critical for obtaining the final part in a quality regime.

Wire Arc Additive Manufacturing (WAAM) is one of the most appropriate additive manufacturing techniques for producing large-scale metal components with a high deposition rate and low cost. Recently, the manufacture of nickel-based alloy (IN718) using WAAM technology has received increased attention due to its wide application in industry. However, insufficient information is available on the mechanical properties of WAAM IN718 alloy, for example in high-temperature testing. In this paper, the mechanical properties of IN718 specimens manufactured by the WAAM technique have been investigated by tensile tests and hardness measurements. The specific comparison is also made with the wrought IN718 alloy, while the microstructure was assessed by scanning electron microscopy and X-ray diffraction analysis. Fractographic studies were carried out on the specimens to understand the fracture behavior. It was shown that the yield strength and hardness of WAAM IN718 alloy is higher than that of the wrought alloy IN718, while the ultimate tensile strength of the WAAM alloys is difficult to assess at lower temperatures. The microstructure analysis shows the presence of precipitates (laves phase) in WAAM IN718 alloy. Finally, the effect of precipitation on the mechanical properties of the WAAM IN718 alloy was discussed in detail.

The symmetrical nature in the case of wall fabrication by wire arc additive manufacturing (WAAM) has been observed in the literature, but it has not been studied as a source of knowledge. This paper focuses on the comparative study of three drop transfer methods employing Gas Metal Arc Welding (GMAW) technology, one of the most reported for the manufacture of aluminum alloys. The transfer modes studied are the well-known pulsed GMAW, cold arc, and the newer pulsed AC. The novelty of the last transfer mode is the reversal of the polarity during the preparation phase of the substance for droplet deposition. This study compares the symmetry of zero beads to determine the best parameters and transfer modes for wire arc additive manufacturing of 5 series aluminum. The pulsed transfer modes show values of 0.6 for symmetry ratio, which makes them more interesting strategies than cold arc with a symmetry ratio of 0.5. Furthermore, the methodology proposed in this study can be extrapolated to other materials manufactured with this technology.

Delamination is the major failure mechanism in composite laminates and eventually leads to material failure. An early-detection and a better understanding of this phenomenon, through non-destructive assessment, can provide a proper in situ repair and allow a better evaluation of its effects on residual strength of lightweight structural components. Here we adopt a joint numerical-experimental approach to study the effect of delamination on the fatigue life of glass/epoxy composites. To identify and monitor the evolution of the delamination during loading, we carried out stepwise cyclic tests coupled with IR-thermography on both undamaged and artificially-damaged samples. The outcome of the tests shows that IRthermography is able to identify a threshold stress, named damage stress σ D , which is correlated to the damage initiation and the fatigue performance of the composite. Additionally, we performed FE-simulations, implementing the delamination by cohesive elements. Such models, calibrated on the basis of the experimental fatigue results, can provide a tool to assess the effect of parameters, such as the delamination size and location, and composite stacking sequence, on the residual strength and fatigue life of the composite material.

The design of parts in such critical sectors as the manufacturing of aeronautical parts is awaiting a paradigm shift due to the introduction of additive manufacturing technologies. The manufacture of parts designed by means of the design-oriented additive manufacturing methodology (DfAM) has acquired great relevance in recent years. One of the major gaps in the application of these technologies is the lack of studies on the mechanical behavior of parts manufactured using this methodology. This paper focuses on the manufacture of a turret for the clamping of parts for the aeronautical industry. The design of the lightened turret by means of geometry optimization, the manufacture of the turret in polylactic acid (PLA) and 5XXX series aluminum alloy by means of Wire Arc Additive Manufacturing (WAAM) technology and the analysis by means of finite element analysis (FEA) with its validation by means of a tensile test are presented. The behavior of the part manufactured with both materials is compared. The conclusion allows to establish which are the limitations of the part manufactured in PLA for its orientation to the final application, whose advantages are its lower weight and cost. This paper is novel as it presents a holistic view that covers the process in an integrated way from the design and manufacture to the behaviour of the component in use.

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