Influence of ultrasonic processing on the mechanical properties of metals subjected to intense plastic deformation

Abstract

An original device for production of nanostructured materials by the method of severe plastic deformation with the imposition of ultrasonic vibrations is described, which provides the grinding of the structure of the material of the workpiece and eliminates the occurrence of defects on its surface and in the end areas. This effect is achieved through the use of an annular spacer made in the form of a hollow waveguide of resonant length, fixed on a fixed support in the displacement unit, connected to a concentrator and an ultrasonic transducer. The physical-mechanical properties of nanostructured samples of nickel and copper after ultrasonic treatment (UST) have been studied. It is shown that UST of nanostructured samples leads to an increase in their plastic properties and a slight decrease in the tensile strength. At small amplitudes of mechanical stresses within 17.5 MPa, a noticeable microhardness increase is observed in copper and nickel samples. A further increase in the mechanical stress amplitude up to 100 MPa during ultrasonic treatment leads to a microhardness decrease.