Interest in magnesium alloys and their applications has risen in recent years. This trend is mainly evident in casting applications, but wrought alloys are also increasingly coming into focus. Among the most common forming processes, forging is a promising candidate for the industrial production of magnesium wrought products. This review is intended to give a general introduction into the forging of magnesium alloys and to help in the practical realization of forged products. The basics of magnesium forging practice are described and possible problems as well as material properties are discussed. Several alloy systems containing aluminum, zinc or rare earth elements as well as biodegradable alloys are evaluated. Overall, the focus of the review is on the process control and processing parameters, from stock material to finished parts. A discussion of the mechanical properties is included. These data have been comprehensively reviewed and are listed for a variety of magnesium forging alloys.

The low mass and high specific stiffness of Mg alloys make them particularly interesting as means of transportation. Due to further desirable properties, such as good machinability and excellent castability, Mg alloys have gained acceptance as castings in high-volume applications, such as gearbox housings and automotive steering wheels. However, in forming processes, such as extrusion and forging, Mg alloys find little to no industrial use at the moment. The reasons for this are their poor formability, which is reflected in limited processing speeds and low ductility, and their modest mechanical performance, compared to competing materials, such as Al alloys and high-strength steels. Much research is being conducted worldwide on high-strength Mg alloys, most of which rely on high levels of rare earths, making these materials both ecologically and economically questionable. Here, it is shown that high yield strengths (>300 MPa) can be achieved in the Mg–Al–Ca system while maintaining good ductility, using only low-cost elements. The investigations have shown that these properties can be adjusted over broad alloy compositions, which greatly simplifies both the processing and recyclability.

Ti-6Al-4V has a wide range of applications, but long lead times and low-efficiency processing of the material leads to limitations. Through additive manufacturing, such as wire-arc directed energy deposition, higher processing efficiency, and lower lead times are possible. To fully realize the benefits, an important parameter for application is the fatigue performance, which needs to be better documented and performance shortcomings improved. Currently, available results on fatigue performance of wire-arc directed energy deposition of Ti-6Al-4V are limited. Therefore, wire-arc directed energy deposition of Ti-6Al-4V was used with the following approach. Samples were characterized using scanning electron microscopy and optical light microscopy, and mechanically tested for tensile and fatigue performance. Minimal pore density and a fine α microstructure within coarsened epitaxial columnar β-grains was observed. Additionally, elemental burn-off and oxygen contamination was assessed, showing a loss of 0.2 wt.% aluminum during processing and no oxygen pick-up. Compared to other cold metal transfer-based wire-arc directed energy deposition results available in the literature, the results present significant improvements. Fractography indicated mixed fracture modes, which are likely due to the macro-zones of α having varying orientations. Our work provides an advancement in fatigue performance and processing, further showing the potential of the technology.