Exploring the Relative Influence of Atomic Parameters on Solid Solution Strengthening

This study designed and produced FCC solid solution alloys with significant differences in atomic volume or electronegativity among the constituent elements, and subjected them to mechanical testing. The results demonstrate that atomic volume differences have a greater influence on solid solution strengthening (SSS) than electronegativity differences. Each solid solution system exhibits unique behavior, making a general model for predicting SSS challenging. Additionally, for a given solid solution system, there is a considerable difference in the critical grain size below which grain boundary strengthening dominates yield strength and hardness. Furthermore, both predicted lattice distortion values and the measured SSS components were greater for binary alloys, indicating that the presence of more elements in a solid solution does not always cause greater distortions in the crystal lattice. Finally, the study successfully engineered the novel Ni ₅₀ Pd ₅₀ alloy, which has not been previously studied and exhibits mechanical properties remarkably insensitive to variations in grain size, warranting further in-depth investigations.