Nickel-titanium-copper memory alloy is a new alloy material invented by researchers from keele university in Germany. Its deformation times can reach 10 million times without fracture, while usually the alloy material will fracture after deformation for thousands of times. This new material will be widely used in many fields such as microelectronics and optical components, sensors and medical devices.
When heated and cooled the alloy deforms and soon returns to its original shape as it was originally machined. But most of the alloy in the condition of two kinds of lattice shift thousands of times, can appear crack and even broken, keele university in Germany expert vigorously in a paper published in the journal science, explains that this is because the metal high temperature phase (austenitic) there will be more and more low temperature phase (martensite) crystal structure, the transformation between the two phase not completely alloy fracture.
However, researchers at keele university in Germany invented a new niti copper memory alloy in 2015 that can deform tens of millions of times without breaking. A zinc-gold-copper memory alloy invented two years ago by university of Minnesota expert James Williams has similar properties. The alloy can withstand 16,000 cold and hot deformations without cracking.
Using high-power electron microscopy and X-ray tests at temperatures ranging from 22 degrees Celsius to 87 degrees Celsius, the researchers found that the alloy's components -- 54 titanium atoms, 34 nickel atoms and 12 copper atoms -- could undergo tens of millions of deformations without cracking. The researchers can also see under a microscope that when the martensite is completely transformed into an austenitic, two titanium and copper atoms deposit in the lattice, and the titanium and copper atoms deposit to form the basic structure of the crystal in both phases, a phenomenon they call epitaxial growth.
