Researchers at North Carolina State University and the Chinese Academy of Sciences have developed a technique to make titanium stronger without sacrificing any of the metal’s ductility – a combination that no one has achieved before. The researchers believe the technique could also be used for other metals, and the advance has potential applications for creating more energy-efficient vehicles.
The key idea here is grain size, or the size of the crystals in the metal. Metals with a small grain size are stronger – meaning they can withstand more force before they start to deform. But metals with a small grain size are also less ductile, which means they can withstand less strain before breaking. Materials that aren’t ductile won’t bend or stretch much – they just snap. Conversely, metals with a large grain size are more ductile, but have lower strength.
The new technique manipulates the grain size to give the metal the strength of ultrafine-grained titanium but the ductility of coarse-grained titanium.