Al 2024 alloy is one of the most widely used alloys in the aerospace industry owing to its high
strength-to-weight ratio, excellent fracture toughness, and fatigue properties. However, the additive
manufacturing of the additively manufactured Al 2024 alloy is scarce in literature due to its high
solidification cracking and low processing window. This is primarily due to the fact that the
composition of the Al 2024 alloy is not well-suited for additive manufacturing. The high solidification
range of the Al 2024 alloy (135 K) coupled with the columnar grains formed in the additive
manufacturing due to extreme thermal gradient ( K/s) promotes solidification cracking along the grain
boundaries in the additively manufactured Al 2024 alloy. The solidification cracking can be reduced
by promoting the columnar to equiaxed transformation and by tailoring the composition that is better
suited for the additively manufactured Al 2024 alloy. The current study explores the Ti addition in Al
2024 alloy as Ti has been conventionally used as the grain refining agent in the casting; however,
studies investigating the grain refining effect of Ti on additively manufactured Al alloy are scarce in
the literature.
The various mechanical properties such as tensile, hardness, fracture toughness, fatigue life, and
fatigue crack growth behaviour were investigated for laser powder bed fusion (LPBF) fabricated Ti-
modified Al 2024 alloy. The corresponding microstructural features were investigated with different
characterisation techniques such as scanning electron microscopy (SEM), transmission electron
microscopy (TEM), electron backscattered diffraction (EBSD). The microstructural features such as
grain size, precipitate dislocation interaction, etc, were correlated with the mechanical properties of Ti
addition in additively manufactured Al 2024 alloy. The fully equiaxed ultra-fine grained
microstructure with an average grain size of 0.4 was observed in the alloy. The present work has
shown that tensile strength, fracture toughness, and fatigue crack growth behaviour of the additively
manufactured Al 2024 alloy are comparable to the conventional wrought counterparts, and the yield
strength, hardness, and fracture toughness were better compared to the conventional wrought
counterparts.
The mechanical properties obtained were further utilised to design lightweight prototypes of
structural components of Al 2024 alloy for aerospace applications. The different lightweight

methodologies, such as topology optimisation and internal lattice structure, were combined to explore
the maximum weight reduction without compromising the strength of the component. The
combination of topology optimisation and internal lattice structure resulted in 24.3% and 52.5%
weight reduction in two aerospace engine brackets.