Two-stage Hall-Petch relationship in Cu with recrystallized structure

摘要

Although Cu was studied extensively,the Hall-Petch relationship was mainly reported in the coarsegrained regime.In this work,fully recrystallized Cu specimens with a wide grain size regime of 0.51–14.93μm manifest a two-stage Hall-Petch relationship.There is a critical grain size of 3μm that divides stagesⅠandⅡwhere the Hall-Petch slope k value are quite different.The stageⅡis supposed to be validified down to 100 nm at least by comparing with a Cu-Ag alloy.The critical grain size varies in different materials systems,and the underline mechanisms are discussed based on the dislocation glide modes.