The performance of nano-Y2O3-reinforced ZK60 matrix nanocomposites prepared by powder metallurgy

Abstract

The nano-Y2O3-reinforced ZK60 alloys are successfully prepared via powder metallurgy (PM) combined with hot-pressing sintering, and the effects of nano-Y2O3 particle addition on the microstructure, corrosion resistance and mechanical properties of ZK60 alloys are studied. The results show that for the extruded samples, with the addition of nano-Y2O3 particles to the ZK60 matrix, the average grain size is reduced to the nanoscale (750 nm), and the coefficient of thermal expansion (CTE) is decreased, with proper addition of nano- Y2O3 particles can improve the strength, ductility and corrosion resistance meanwhile. The ultimate tensile strength and ductility of the extruded 0.3Y2O3/ZK60 composites are 336.5 MPa and 14.3 %, respectively. The increment in the ductility reaches 38.8 % relative to the initial ZK60 alloys, which achieves favorable strength plasticity product matching (UT = 4812 MPa%). However, excessive addition of nano-Y2O3 particles and the agglomeration of nano-Y2O3 particles around the grain boundary can lead to dislocation pinning and dislocation movement deterrence, but this also results in interface combination deterioration. The mainly contributions to the mechanical properties are grain refinement, dislocation strengthening and Orowan strengthening; Moreover, the molecular dynamics (MD) simulations results show the interaction of nano-Y2O3 particle and dislocation is bypassing behavior.