Bearing Aluminum-Based Alloys: Microstructure, Mechanical Characterizations, and Experiment-Based Modeling Approach

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Materials Science

Background:

• Engine bearing alloys require high mechanical and tribological properties due to start/stop systems and load variations.
• Al-rich anti-friction alloys can be enhanced by incorporating additional elements to improve performance.

Purpose of the Study:

• To develop an artificial neural network (ANN) for accurate modeling and prediction of mechanical properties in aluminum-based bearing alloys.
• To optimize the chemical composition of these alloys for superior mechanical characteristics.
• To investigate the influence of soft and solid phases on alloy mechanical properties.

Main Methods:

• Casting and annealing of 198 unique aluminum-based alloys with varying compositions (Sn, Pb, Cu, Mg, Zn, Si, Ni, Bi, Ti, Mn, Fe, Al).
• Microstructural analysis to identify soft (Sn-rich, Sn-Pb, Pb-Sn) and solid (Al2Cu) phases.
• Testing of mechanical properties: ultimate tensile strength (σu), Brinell hardness (HB), and elongation to failure (δ).
• Construction and optimization of an ANN architecture with two hidden layers and 20 neurons each.

Main Results:

• The optimal ANN achieved high prediction accuracy: R=0.94, RMSE=3.5, AARE=1.0%.
• Microstructural analysis confirmed the presence of beneficial soft and solid phases.
• The developed alloys exhibited excellent tribological characteristics and met mechanical property requirements, with maximum values: σu = 197 ± 7 MPa, HB = 77 ± 4, and δ = 20.3 ± 1.0%.
• Model validation demonstrated accurate prediction of new alloy characteristics (R ≥ 0.97, RMSE = 1-2.65, AARE < 10%).

Conclusions:

• The ANN model effectively predicts mechanical properties, enabling optimization of aluminum-based bearing alloy compositions.
• The study highlights the critical role of soft (Sn, Pb) and solid (Cu) phases in achieving desired mechanical performance.
• This approach facilitates the development of advanced anti-friction materials for demanding engine applications.