Synergistic Strengthening: Tailoring Microstructure and Maximizing Dry Sliding Wear Resistance in Al-Ni Alloys

Lightweight and durable materials like Al-Ni alloys are needed for applications demanding high-strengthto-weight ratios, such as in the automotive and aerospace industries. This study investigated the
microstructural evolution and mechanical properties of stir cast Al-Ni alloys (5-7 wt.% Ni) and optimized
their dry sliding wear behavior using the Taguchi-Gray relational analysis. Increasing nickel content led to
a higher volume fraction of the hard Al3Ni intermetallic phase, confirmed by XRD and EDS analyses. This
resulted in a 2.6% increase in ultimate tensile strength (Al-7 wt.% Ni compared to Al-5 wt.% Ni).
Increasing the nickel content in the stir cast Al-Ni alloys resulted in enhanced hardness, with the Al-7 wt.%
Ni alloy exhibiting a 3.37% higher hardness than the Al-5 wt.% Ni alloy, primarily attributed to the
formation of hard Al3Ni intermetallics and solid solution strengthening. The density also slightly increased
with higher Ni content due to the substitution of Al atoms with heavier Ni atoms. Sliding distance and
applied load were identified as the most significant factors affecting wear, while nickel content had a less
dominant influence. Multi-objective optimization resulted in a 14.1% improvement in dry sliding performance, with the gray relational grade improving by 86.8% from the initial to the optimal wear test settings.
This study highlights the positive correlation between microstructural features, mechanical properties, and
wear resistance in Al-Ni alloys.