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Remanufacturing and Advanced Machining
laser-based AM process exhibited the highest tensile strength of 530 MPa along the
build orientation and a remarkably elevated hardness after aging treatment, revealing a potential to become a highly demanded material for aerospace applications.
Due to their low weight and promising strength characteristics, Mg and its alloys
are widely used by aeronautical industries tending to replace heavier Al alloys. Mg
alloys are also used as an alternative replacement for plastics, since they have more
stiffness than and density comparable with plastics. Additionally, when Mg alloys
are doped with rare earth elements, they show an enhanced corrosion resistance as
well. It should be noted that processing of Mg alloys brings the risk of firing when a
material is a powder or at higher temperatures, which limits the use of Mg alloys in
aerospace industries. Nevertheless, different AM techniques can be adapted for fabricating magnesium components and medical implants with a reduced ignition risk,
e.g., PBF methods, WAAM, FDM, friction stir AM, and binder jetting techniques.
Ti alloys are widely used in aerospace and biomedical applications due to their
predominant properties, such as higher specific strength and outstanding corrosion
resistance. These superior properties enable Ti alloys to be used for high-temperature and strength applications such as blades and cases of steam turbine and turbo
engines. While manufacturing of Ti alloy components with conventional techniques
is challenging due to their low thermal conductivity and affinity with cutting tool
materials, laser-based AM techniques are effective methods of Ti-based alloys processing. In particular, electron beam AM techniques can produce Ti alloy parts of
higher densities than obtainable by SLM. There are a few Ti-based alloys recently of
interest to researchers, such as Ti6Al4V, Ti8Al1Er, TC11, TC21, and Ti5553, commonly used for AM fabrication of components. In particular, Ti6Al4V alloy, known
also as Ti64 alloy, is a widely accepted α+β Ti alloy that accounts for nearly half of
the Ti market share around the world. Another alloy processed with laser-based AM
is Ti-6.5Al-3.5Mo-1.5Zr-0.3Si, sometimes referred to as TC11, which is widely used
in compressor disks and other aerospace applications due to its capacity to withstand
high strains during loading.
Ni-based superalloys such as Inconel 625 and 718 are primarily used to fabricate critical components, such as gas turbine engines and compressors, that regularly undergo high temperatures and stresses. They can be fabricated by the EBM
or laser-based AM processes, as well as binder jetting in the case of the Inconel 718
alloy. On the other hand, Co-based alloys, e.g., CoCr, are used for dental and other
biomedical applications. The AM-prepared Ni–Co-based alloys reportedly produce
synchronous improvements to both microstructure and mechanical properties as Co
inclusion rises. AM of Ni-based shape memory alloys (SMAs) is another exciting,
rapidly developing research field. These alloys can be deformed in cold conditions,
but when they are subjected to heat, the element regains its pre-deformed shape
due to a phase transformation induced by heat. NiTi and Cu–Al–Ni are considered
to be the most common SMAs used in aerospace applications, biomedical applications, and conventional actuators for pneumatic, hydraulic, and motor-based systems
(Kumar and Sathiya, 2021).
As emphasized by Cooke et al. (2020), metal AM systems require a metal feedstock
to be melted and deposited on a substrate to then construct layers which eventually
Remanufacturing and Advanced Machining
laser-based AM process exhibited the highest tensile strength of 530 MPa along the
build orientation and a remarkably elevated hardness after aging treatment, revealing a potential to become a highly demanded material for aerospace applications.
Due to their low weight and promising strength characteristics, Mg and its alloys
are widely used by aeronautical industries tending to replace heavier Al alloys. Mg
alloys are also used as an alternative replacement for plastics, since they have more
stiffness than and density comparable with plastics. Additionally, when Mg alloys
are doped with rare earth elements, they show an enhanced corrosion resistance as
well. It should be noted that processing of Mg alloys brings the risk of firing when a
material is a powder or at higher temperatures, which limits the use of Mg alloys in
aerospace industries. Nevertheless, different AM techniques can be adapted for fabricating magnesium components and medical implants with a reduced ignition risk,
e.g., PBF methods, WAAM, FDM, friction stir AM, and binder jetting techniques.
Ti alloys are widely used in aerospace and biomedical applications due to their
predominant properties, such as higher specific strength and outstanding corrosion
resistance. These superior properties enable Ti alloys to be used for high-temperature and strength applications such as blades and cases of steam turbine and turbo
engines. While manufacturing of Ti alloy components with conventional techniques
is challenging due to their low thermal conductivity and affinity with cutting tool
materials, laser-based AM techniques are effective methods of Ti-based alloys processing. In particular, electron beam AM techniques can produce Ti alloy parts of
higher densities than obtainable by SLM. There are a few Ti-based alloys recently of
interest to researchers, such as Ti6Al4V, Ti8Al1Er, TC11, TC21, and Ti5553, commonly used for AM fabrication of components. In particular, Ti6Al4V alloy, known
also as Ti64 alloy, is a widely accepted α+β Ti alloy that accounts for nearly half of
the Ti market share around the world. Another alloy processed with laser-based AM
is Ti-6.5Al-3.5Mo-1.5Zr-0.3Si, sometimes referred to as TC11, which is widely used
in compressor disks and other aerospace applications due to its capacity to withstand
high strains during loading.
Ni-based superalloys such as Inconel 625 and 718 are primarily used to fabricate critical components, such as gas turbine engines and compressors, that regularly undergo high temperatures and stresses. They can be fabricated by the EBM
or laser-based AM processes, as well as binder jetting in the case of the Inconel 718
alloy. On the other hand, Co-based alloys, e.g., CoCr, are used for dental and other
biomedical applications. The AM-prepared Ni–Co-based alloys reportedly produce
synchronous improvements to both microstructure and mechanical properties as Co
inclusion rises. AM of Ni-based shape memory alloys (SMAs) is another exciting,
rapidly developing research field. These alloys can be deformed in cold conditions,
but when they are subjected to heat, the element regains its pre-deformed shape
due to a phase transformation induced by heat. NiTi and Cu–Al–Ni are considered
to be the most common SMAs used in aerospace applications, biomedical applications, and conventional actuators for pneumatic, hydraulic, and motor-based systems
(Kumar and Sathiya, 2021).
As emphasized by Cooke et al. (2020), metal AM systems require a metal feedstock
to be melted and deposited on a substrate to then construct layers which eventually