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Engineering Science in
Additive Manufacturing Multi-material additive manufacturing of metals

Ni alloys with lightweight Al, the process introduces In aerospace and nuclear industries, components could
significant challenges. These challenges stem from the be fabricated with spatially varying properties to withstand
intrinsic differences in thermophysical properties that both mechanical loads and radiation damage. Biomedical
were discussed in detail in this article, such as melting implants could combine biocompatible surfaces with
points, thermal conductivity, and CTE, often leading to load-bearing cores, all within a single manufacturing
residual stresses, cracking, and brittle intermetallic phase process. In conclusion, the future of MMAM with discrete
formation. Addressing these issues represents a critical metal transitions hinges on the convergence of material
frontier in MMAM research and development. science, advanced modeling, real-time sensing, and
data-driven control. By developing intelligent interlayer
A promising future direction lies in the deliberate designs and integrating process monitoring with adaptive
design and fabrication of compositionally graded manufacturing strategies, the field is positioned to
interlayers and engineered interface architectures that overcome longstanding metallurgical barriers and enable
facilitate smooth transitions between dissimilar metals. a new generation of multifunctional, high-performance
Instead of abrupt material changes—which may offer components.
advantages in certain applications but often introduce sites
of mechanical weakness or metallurgical incompatibility— Abbreviations
graded transitions and/or IBLs allow for gradual variations
in composition and microstructure. These interlayers can 3D Three-dimensional
mitigate thermal mismatch, reduce stress concentrations, AE Acoustic emission
and suppress the formation of brittle intermetallics, AM Additive manufacturing
thereby enabling strong, defect-free metallurgical bonding. BCC Body-centered cubic
To advance this strategy, several enabling technologies and CALPHAD Calculation of phase diagram
Computer-aided design
CAD
research methodologies must be leveraged. Computational CFD Computational fluid dynamics
alloy design tools informed by CALPHAD databases and CFD-DEM Computational fluid dynamics – discrete element
density functional theory can predict phase stability and method
guide the development of transition compositions that CFD-VOF Computational fluid dynamics – volume of fluid
optimize bonding without compromising functionality. CTE Coefficient of thermal expansion
Coupled with this, data-driven approaches such as machine DEM Discrete element method
learning can be employed to refine the process parameters DEM-SPH Discrete element method – smoothed particle
in real time, using data from prior builds to predict optimal hydrodynamics
conditions for layer deposition and fusion quality. DIC Digital image correlation
EB-PBF Electron beam powder bed fusion
Another key enabler that was discussed in this
section is in situ monitoring during the printing process. EBSD Electron backscatter diffraction
EDS
Energy dispersive spectroscopy
Techniques such as optical pyrometry, thermal imaging, F Compression
com
and AE sensing can provide real-time feedback on the FCC Face-centered cubic
thermal environment and melt pool dynamics, allowing FEA Finite element analysis
immediate adjustment of laser power, scan speed, or F Fatigue
feedstock composition. These monitoring strategies can F fat Shear
provide valuable data for post-build quality assurance F shear Thermal diffusivity
therm
and digital twin development. Furthermore, multiscale F wear Wear performance
modeling and simulation play a vital role in predicting the FGM Functionally graded material
evolution of thermal gradients, phase transformations, FGM-LDED Functionally graded material laser-direct energy
and stress fields across the transition zone. By simulating deposition
the build process from the microstructural to the FSW Friction stir welding
component scale, researchers can anticipate failure HV Hardness Vickers
modes and iterate on interface designs before fabrication. IBL Intermediate bonding layer
The successful implementation of discrete metal IMC Intermetallic compound
transitions through MMAM unlocks a wide range of IR Infrared
application opportunities. For example, heat exchangers LDED Laser-direct energy deposition
can be designed with Cu-rich regions for high thermal LPBF Laser powder bed fusion
conductivity seamlessly bonded to SS for structural LAMMPS Large-scale atomic/molecular massively parallel
simulator
support and corrosion resistance.

Volume 1 Issue 2 (2025) 33 doi: 10.36922/ESAM025180010