When it comes to vehicle manufacturing, aluminum offers very desirable characteristics-light weight and corrosion resistance. However, it may also encounter some troubles, such as repeated and alternating pressures will reveal its weaknesses. Imagine here that if you repeatedly bend a paperclip, it will eventually break. To this end, Australian scientists have proposed a solution-the so-called "fatigue failure" method, that is, by modifying the microstructure of the aluminum alloy to repair these weaknesses by itself.
Professor Christopher Hutchinson from Monash University who led the research pointed out: "80% of engineering alloy failures are due to fatigue. Fatigue is a failure caused by alternating stress, which is a major event in the manufacturing and engineering industries. ."
The research conducted by Hutchinson and his team is the first of its kind, focusing on the underlying causes of fatigue known as precipitation-free zones (PFZs). These weak links are formed in the aluminum alloy through alternating stresses, initially just tiny plastic points, and then cracks will form before finally breaking the material.
Hutchinson and his team of engineers tried to intervene in the early stages of this process by using the mechanical energy generated during alternating stresses. More specifically, the team came up with a way to capture the new particles formed when stress acts on the material, and then use these particles to strengthen the weak links and significantly delay the appearance of cracks.
This is achieved through a "training" process that mimics the tension on the material and needs to be repeated hundreds of times. The advantage of this is that it can have a higher concentration of fine particles in the weak area to improve the yield and tensile strength of the material, and then it can achieve self-healing during operation.
The researchers said that modifying the starting structure in this way can significantly increase the fatigue life of aluminum alloys. In addition, they pointed out that the fatigue strength of high-strength aluminum alloys is very low, but they get the most benefits, and their fatigue life can be extended by 25 times.