Chinese scientists have created an alloy with sverkhreshetkakh structure, which has outstanding heat resistance and ductility at room temperature. Disordered interfacial structure of nano layer differed significantly from that observed previously in similar alloys. Its presence enabled the material to withstand loads up to 1.6 GPA and to take 25 percent. The results of a study published in Science.
Protoopalina alloys with ordered structure, belong to the class of structural materials with intermediate properties between metals and ceramics. Such alloys with sverkhreshetkakh structure potentially suitable for the creation of structures that experience high loads at high temperatures. However, they have poor ductility and thermal stability, therefore, brittle at room temperatures and soft at high. To solve this problem by growing a single large crystal, but it would be difficult, expensive and time consuming.
Tao Yang (Tao Yang) with colleagues from the City University of Hong Kong suggested that the properties of such alloys can be improved by forming nano-sized disordered region between the phases in the alloy. Using arc melting, thermomechanical processing and controlled input of several chemical elements, the authors synthesized an alloy of Nickel, cobalt, iron, aluminum, titanium and boron, and studied the structure and mechanical properties.
The materials obtained had a polycrystalline morphology with an average grain size of about 11 microns. Grain had sverkhreshetkakh structure, and divided the disordered interfacial nano layer. Using energy dispersive x-ray spectroscopy, the researchers found that the titanium atoms and aluminum prefer to be at the vertices of cells of a crystalline face-centered cubic lattice and centers of faces is primarily the atoms of Nickel and cobalt. The iron atoms occupy both sides of a sublattice cell, which allows the alloy to be stoichiometric. This structure suppresses the formation of brittle hexagonal or tetragonal phases.