When subjected to particular levels of stress, metals can revert to their original shape due to elasticity. Materials with large elastic deformation provide greater flexibility in items including sporting goods and medical devices.
Theoretically, most metals and alloys can endure a strain value of about 10 per cent when the metals are reduced to micro or nano scales. When these metals are in their bulk shape, as they are for most practical engineering applications, the elastic strain drops below one per cent.
Led by Sheng Xu, specially appointed assistant professor at Tohoku University's Graduate School of Engineering, the group's bulk copper-based alloy demonstrated a tensile elastic strain greater than 4.3 per cent at room temperature.
The elastic softening behaviour exhibited by the material meant that the relationship between tensile stress and strain was not linear and did not adhere to Hooke's law, a theory of elasticity generalising that the elasticity of an object is proportional to the stress applied.
The new material, however, presented a Young's modulus of less than 25GPa and a large Poisson's ratio of 0.47, making the material highly elastic - even when exposed to small amounts of stress - and notably strong.
The team added that cyclic heat treatment can be used to prepare the bulk single crystals of the alloy, a process that enables it to be mass produced.
"Our bulk alloy can be used as spring materials with high recoverability, and they could also be applied to devices that employ strain-mediated sensors, such as stretchable electronics" Xu said in a statement. "The new alloy's low Young's modulus resembles human bones and therefore has the potential for use in medical applications."
Details of the research have been published in Nature Communications.
The research group will now conduct tests on the functional fatigue of large elastic deformations on the alloy, which they said is fundamental for its practical applications. They are collaborating also with industry to explore more applications for the alloy.
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