Friction stir processing (FSP) has attracted much attention in the last decade and contributed significantly to the creation of functionally graded materials with both gradient structure and gradient mechanical properties. Subsurface gradient structures are formed in FSPed metallic materials due to ultrafine grained structure formation, surface modification and hardening with various reinforcing particles, fabrication of hybrid and in situ surfaces. This paper is a review of the latest achievements in FSP of non-ferrous metal alloys (aluminum, copper, titanium, and magnesium alloys). It describes the general formation mechanisms of subsurface gradient structures in metal alloys processed by FSP under various conditions. A summary of experimental data is given for the microstructure, mechanical, and tribological properties of non-ferrous metal alloys.

The work is devoted to a review of modern achievements in the field of wire-feed electron beam additive manufacturing. The features of structure formation in aluminum, copper, titanium, nickel-based alloys, and steels during 3D printing are shown. Aspects of directional solidification during the production of components from various metals and alloys are considered. The prospects for obtaining composite and functionally graded materials based on various metals and alloys using wire-feed electron beam additive manufacturing are determined. The regularities of the structure modification and hardening of additively manufactured materials by the method of friction stir processing were considered. The main purpose of the review is to present additive manufacturing methods, the main focus being on the wire-feed electron beam additive manufacturing of metal alloys.

A review of the state of research in the field of friction stir welding and processing has been carried out. The features of plastic flow in friction stir welding and their connection with the processes of adhesion friction are shown. The main direction of research is related to the features of friction stir welding of titanium alloys. Special attention is paid to the selection of working tool materials from various alloys for friction stir welding and the processing of titanium alloys. The main advantages and disadvantages of applying different types of tools for friction stir welding of titanium alloys are shown. Different mechanisms of tool wear in friction stir welding associated with the interaction of processed material and tools are demonstrated. Information on the influence of tool and material interaction at welding on the mechanical properties and operational characteristics of obtained joints is given.