Abstract
Aluminum alloys are essential materials in cars, airplanes, and buildings because they are strong, lightweight, and resistant to corrosion. One special group, called Al-Mg-Si alloys, becomes stronger through a process known as “age hardening,” where tiny needle-shaped particles—about 10,000 to 30,000 times smaller than the width of a human hair—form inside the metal to make it stronger.
However, in real-world manufacturing, these alloys often sit at room temperature before the final strengthening step. This “natural aging” can accidentally create clusters made up of just a few to several dozen atoms, which are often harmful for the final strength of the material.
My research focused on understanding how these tiny clusters form and evolve, using advanced microscopes and computer models to look at atoms one by one. I discovered that not all clusters are bad—some can actually help if they have the right atomic structure. By carefully adjusting the heat treatment process, especially by adding a short “pre-aging” step, we can encourage the good clusters to form and avoid the bad ones. This leads to materials that are both stronger and more ductile than those currently used in industry.
Even more surprisingly, I found that in some cases, letting the alloy sit for many years at room temperature can lead to better strength and ductility than traditional methods. For the first time, we revealed how tiny atomic clusters evolve step by step into the needle-shaped particles that strengthen the alloy. This opens up new ways to design aluminum parts that are both strong and ductile—ideal for safer, lighter vehicles and more efficient manufacturing.
This work helps us better control the microstructure of aluminum alloys, leading to smarter, more sustainable materials for the future.