(1) The severe plastic deformation was occurred on the surface of SFPB-treated CuW70 alloy, a part of W particles were fragmented and become smaller on the surface, while the Cu particles only exhibit deformation. The thickness of nanostructure surface layer increased depending upon the treatment duration. The well technology was the shot peening
60 min, and the thickness of nanostructure surface layer up to 21 mm.
(2) The grain refinement process of CuW70 alloy involves internal defects proliferation, particles deformation and break up, grain refining of W and strong plastic deformation of Cu bonding phase. Finally, the random orientation of nano-crystal
was formed on the surface.